lte measurement: how to test a device
DESCRIPTION
LTE Measurement: How to test a device This course provides an overview with practical examples and exercises on how to test a LTE-capable device while performing standardized RF measurements such as power, signal quality, spectrum and receier sensitivity, and how to automate these measurements in a simple and cost-effective way. We will present testing of LTE handsets in terms of protocol signaling scenarios and handover to other radio technologies for interoperability. This course will demonstrate end-to-end (E2E), throughput and application testing using the Rohde & Schwarz R&S®CMW500 Wideband Radio Communication Tester. Examles of application tests are voice over LTE, (VoLTE) or Video over LTE.TRANSCRIPT
LTE, UMTS Long Term Evolution LTE measurements – from RF to application testing
Reiner Stuhlfauth
Training Centre
Rohde & Schwarz, Germany
Subject to change – Data without tolerance limits is not binding.
R&S® is a registered trademark of Rohde & Schwarz GmbH & Co. KG. Trade names are trademarks
of the owners.
2011 ROHDE & SCHWARZ GmbH & Co. KG
Test & Measurement Division
- Training Center -
This folder may be taken outside ROHDE & SCHWARZ facilities.
ROHDE & SCHWARZ GmbH reserves the copy right to all of any part of these course notes.
Permission to produce, publish or copy sections or pages of these notes or to translate them must first
be obtained in writing from
ROHDE & SCHWARZ GmbH & Co. KG, Training Center, Mühldorfstr. 15, 81671 Munich, Germany
November 2012 | LTE measurements| 2
Mobile Communications: Fields for testing
l RF testing for mobile stations and user equipment
l RF testing for base stations
l Drive test solutions and verification of network
planning
l Protocol testing, signaling behaviour
l Testing of data end to end applications
l Audio and video quality testing
l Spectrum and EMC testing
November 2012 | LTE measurements| 3
Test Architecture RF-/L3-/IP Application-Test
November 2012 | LTE measurements| 4
LTE: EPS Bearer
P-GWS-GW Peer
Entity
UE eNB
EPS Bearer
Radio Bearer S1 Bearer
End-to-end Service
External Bearer
Radio S5/S8
Internet
S1
E-UTRAN EPC
Gi
S5/S8 Bearer
November 2012 | LTE measurements| 5
Mobile Radio Testing
Core network
A mobile radio tester emulates a
base station
Perform
RF measurements on
received uplink
Generate downlink
signal and send control
commands
Adjust the downlink
signal to how uplink is
received
November 2012 | LTE measurements| 6
Mobile Radio Testing
Signaling testing
Generate downlink
signal and send
signaling information
Non-Signaling testing
Control PC
Generate downlink
signal
No signaling
November 2012 | LTE measurements| 7
LTE measurements general aspects
November 2012 | LTE measurements| 8
LTE RF Testing Aspects UE requirements according to 3GPP TS 36.521 Power
Maximum output power
Maximum power reduction
Additional Maximum Power
Reduction
Minimum output power
Configured Output Power
Power Control
Absolution Power Control
Relative Power Control
Aggregate Power Control
ON/OFF Power time mask
Output RF spectrum emissions
Occupied bandwidth
Out of band emissions
Spectrum emisssion mask
Additional Spectrum emission mask
Adjacent Channel Leakage Ratio
Transmit Intermodulation 36.521: User Equipment (UE) radio
transmission and reception
Transmit signal quality
Frequency error
Modulation quality, EVM
Carrier Leakage
In-Band Emission for non allocated RB
EVM equalizer spectrum flatness
November 2012 | LTE measurements| 9
LTE RF Testing Aspects UE requirements according to 3GPP, cont.
Receiver characteristics: Reference sensitivity level
Maximum input level
Adjacent channel selectivity
Blocking characteristics
In-band Blocking
Out of band Blocking
Narrow Band Blocking
Spurious response
Intermodulation characteristics
Spurious emissions
Performance
November 2012 | LTE measurements| 10
LTE RF Testing Aspects BS requirements according to 3GPP
l Transmitter Characteristics l Base station output power
l Frequency error
l Output power dynamics
l Transmit ON/OFF power
l Output RF spectrum emissions (Occupied bandwidth, Out of band
emission, BS Spectrum emission mask, ACLR, Spurious emission,
Co-existence scenarios,…)
l Transmit intermodulation
l Modulation quality TR 36.804: Base Station (BS) radio
transmission and reception
November 2012 | LTE measurements| 11
LTE RF Testing Aspects BS requirements according to 3GPP, cont.
l Receiver Characteristics l Reference sensitivity level
l Dynamic range
l Adjacent Channel Selectivity (ACS)
l Blocking characteristics
l Intermodulation characteristics
l Spurious emissions
l Performance
November 2012 | LTE measurements| 12
LTE RF Measurements – regional requirements
l Regional / band-specific requirements exist (e.g. spurious emissions)
l Since UEs roam implementation has to be dynamic
Concept of network signaled RF requirements has been introduced with
LTE.
- Network signaled value: NS_01 … NS_32
- transmitted as IE AdditionalSpectrumEmission in SIB2
November 2012 | LTE measurements| 13
LTE bands and channel bandwidth E-UTRA band / channel bandwidth
E-UTRA Band 1.4 MHz 3 MHz 5 MHz 10 MHz 15 MHz 20 MHz
1 Yes Yes Yes Yes
2 Yes Yes Yes Yes Yes[1] Yes[1]
3 Yes Yes Yes Yes Yes[1] Yes[1]
4 Yes Yes Yes Yes Yes Yes
5 Yes Yes Yes Yes[1]
6 Yes Yes[1]
7 Yes Yes Yes Yes[1]
8 Yes Yes Yes Yes[1]
9 Yes Yes Yes[1] Yes[1]
10 Yes Yes Yes Yes
11 Yes Yes[1]
12 Yes Yes Yes[1] Yes[1]
13 Yes[1] Yes[1]
14 Yes[1] Yes[1]
...
17 Yes[1] Yes[1]
...
33 Yes Yes Yes Yes
34 Yes Yes Yes
35 Yes Yes Yes Yes Yes Yes
36 Yes Yes Yes Yes Yes Yes
37 Yes Yes Yes Yes
38 Yes Yes Yes Yes
39 Yes Yes Yes Yes
40 Yes Yes Yes Yes
NOTE 1: bandwidth for which a relaxation of the specified UE receiver sensitivity requirement (Clause 7.3) is allowed.
Not every channel
bandwidth for
every band!
November 2012 | LTE measurements| 14
Tests performed at “low, mid and highest frequency”
lowest EARFCN possible
and 1 RB at position 0
RF p
ow
er
Frequency = whole LTE band
RF p
ow
er
Frequency
RF p
ow
er
Frequency
mid EARFCN
and 1 RB at position 0
Highest EARFCN
and 1 RB at max position
Nominal frequency described by EARFCN (E-UTRA Absolute Radio Frequency Channel Number)
November 2012 | LTE measurements| 15
Test Environment – Test System Uncertainty
36.101 / 36.508
• Temperature/Humidity
-normal conditions +15C to +35C, relative humidity 25 % to 75 %
-extreme conditions -10C to +55C (IEC 68-2-1/68-2-2)
• Voltage
• Vibration
Acceptable Test System Uncertainty (Test Tolerance, TT) defined for each test individually
in 36.521 Annex F (will be ignored further on for the sake of simplicity)
Test Minimum Requirement in TS
36.101
Test
Tolerance
(TT)
Test Requirement in TS 36.521-
1
6.2.2. UE
Maximum Output
Power
Power class 1: [FFS]
Power class 2: [FFS]
Power class 3: 23dBm ±2 dB
Power class 4: [FFS]
0.7 dB
0.7 dB
0.7 dB
0.7 dB
Formula:
Upper limit + TT, Lower limit - TT
Power class 1: [FFS]
Power class 2: [FFS]
Power class 3: 23dBm ±2.7 dB
Power class 4: [FFS]
November 2012 | LTE measurements| 16
LTE RF measurements on base stations
November 2012 | LTE measurements| 17
OFDM risk: Degradation
f
1
MCT
f0 f2
Sa
mp
les
f1 f3 f0 f2 f1 f3
ls n lr n
Channel (ideal)
November 2012 | LTE measurements| 18
OFDM risk: Degradation due to Frequency Offset
f
f
f0 f2
Sa
mp
les
f1 f3 f0 f2 f1 f3
2j nfe
ls n lr n
Channel
November 2012 | LTE measurements| 19
OFDM risk: Degradation due to Clock Offset
f
f0 f2
Sa
mp
les
f1 f3 f0 f2 f1 f3
ls n lr n
Channel
f k
November 2012 | LTE measurements| 20
Subcarrier zero handling
1/TSYMBOL=15kHz
f f-1
f0 f1
Subcarrier 0 or DC subcarrier
causes problems in DAC for
direct receiver strategies, DC offset!
12/
2/
212
,
RBsc
ULRB
RBsc
ULRB
s,CP)(
NN
NNk
TNtfkj
lklleats
2/
1
2)(
,
1
2/
2)(
,
)(
RBsc
DLRB
s,CP)(
RBsc
DLRB
s,CP)(
NN
k
TNtfkjp
lkNNk
TNtfkjp
lk
pl
ll eaeats
Downlink:
Uplink:
DC subcarrier ½ subcarrier
offset
DC subcarrier,
suppressed
f-1 f+1
November 2012 | LTE measurements| 21
LTE: DC subcarrier usage
DC subcarrier or subcarrier 0 is not used in downlink!
November 2012 | LTE measurements| 22
DC offset – possible reasons
PLL
1st mixer
fLO
fRX=fLO+fBB+fLO_ɛ
fBB=fRx-fLO
Idea: set PLL to frequency fLO to get frequency of baseband
as fBB = fRX – fLO
But: if synthesizer has leakage: fLO_ɛ will spread into the input:
At the output we get direct current, DC!
fLO_ɛ
fLO –fLO_ɛ=DC
Non-linearities of
Amplifier also cause
DC in the signal
fBB + DC
DC offset originated by mixer:
November 2012 | LTE measurements| 23
Base station test models Parameter 1.4 MHz 3 MHz 5 MHz 10 MHz 15 MHz 20 MHz
Reference, Synchronisation Signals
RS boosting, PB = EB/EA 1 1 1 1 1 1
Synchronisation signal EPRE / ERS [dB] 0.000 0.000 0.000 0.000 0.000 0.000
Reserved EPRE / ERS [dB] -inf -inf -inf -inf -inf -inf
PBCH
PBCH EPRE / ERS [dB] 0.000 0.000 0.000 0.000 0.000 0.000
Reserved EPRE / ERS [dB] -inf -inf -inf -inf -inf -inf
PCFICH
# of symbols used for control channels 2 1 1 1 1 1
PCFICH EPRE / ERS [dB] 3.222 0 0 0 0 0
PHICH
# of PHICH groups 1 1 1 2 2 3
# of PHICH per group 2 2 2 2 2 2
PHICH BPSK symbol power / ERS [dB] -3.010 -3.010 -3.010 -3.010 -3.010 -3.010
PHICH group EPRE / ERS [dB] 0 0 0 0 0 0
PDCCH
# of available REGs 23 23 43 90 140 187
# of PDCCH 2 2 2 5 7 10
# of CCEs per PDCCH 1 1 2 2 2 2
# of REGs per CCE 9 9 9 9 9 9
# of REGs allocated to PDCCH 18 18 36 90 126 180
# of <NIL> REGs added for padding 5 5 7 0 14 7
PDCCH REG EPRE / ERS [dB] 0.792 2.290 1.880 1.065 1.488 1.195
<NIL> REG EPRE / ERS [dB] -inf -inf -inf -inf -inf -inf
PDSCH
# of QPSK PDSCH PRBs which are boosted 6 15 25 50 75 100
PRB PA = EA/ERS [dB] 0 0 0 0 0 0
# of QPSK PDSCH PRBs which are de-boosted 0 0 0 0 0 0
PRB PA = EA/ERS [dB] n.a. n.a. n.a. n.a. n.a. n.a.
TS 36.141
Defines several
Test models
For base station
e.g. E-TM1.1
November 2012 | LTE measurements| 24
Base station unwanted emissions
Spurious domain
RB
Channel bandwidth Spurious domain
ΔfOOB
ΔfOOB
E-UTRA Band
Worst case:
Ressource Blocks allocated
at channel edge
ACLR Spurious emissions
•Adjacent channel leakage
•Operating band unwanted emissions
November 2012 | LTE measurements| 25
Adjacent Channel Leakage Ratio - eNB
E-UTRA transmitted
signal channel
bandwidth
BWChannel [MHz]
BS adjacent channel
centre
frequency offset
below the first
or above the last
carrier centre
frequency
transmitted
Assumed
adjacent
channel
carrier
(informative)
Filter on the
adjacent
channel
frequency and
corresponding
filter bandwidth
ACLR
lim
it
1.4, 3.0, 5, 10, 15, 20 BWChannel E-UTRA of same
BW
Square (BWConfig) 45 dB
2 x BWChannel E-UTRA of same
BW
Square (BWConfig) 45 dB
BWChannel /2 + 2.5
MHz
3.84 Mcps UTRA RRC (3.84 Mcps) 45 dB
BWChannel /2 + 7.5
MHz
3.84 Mcps UTRA RRC (3.84 Mcps) 45 dB
NOTE 1: BWChannel and BWConfig are the channel bandwidth and transmission bandwidth configuration
of the E-UTRA transmitted signal on the assigned channel frequency.
NOTE 2: The RRC filter shall be equivalent to the transmit pulse shape filter defined in TS 25.104 [6],
with a chip rate as defined in this table. Limit is either -13 / -15dBm absolute or as above
Large bandwidth
November 2012 | LTE measurements| 26
Adjacent channel leakage power ratio
November 2012 | LTE measurements| 27
A
Ref 0 dBm Att 25 dB
EXT
1 AP
VIEW
Center 1.947 GHz Span 25 MHz2.5 MHz/
2 AP
VIEW
CLRWR
*
3DB
RBW 10 kHz
SWT 250 ms
VBW 30 kHz
3 AP
*
-100
-90
-80
-70
-60
-50
-40
-30
-20
-10
0
Date: 21.AUG.2008 15:51:00
ACLR measurement
fCarrier fUTRA, ACLR2 fUTRA, ACLR1
UTRAACLR1
= 33 dB
UTRAACLR2
= 36 dB UTRAACLR2bis
= 43 dB
Additional requirement for
E-UTRA frequency band I,
signaled by network to the UE
November 2012 | LTE measurements| 28
Operating band unwanted emissions
dBMHz
offsetfdBm
05.0
_
5
77
Frequency offset
of measurement
filter -3dB point, f
Frequency offset of
measurement filter centre
frequency, f_offset
Minimum requirement Measurem
ent
bandwidth
(Note 1)
0 MHz f < 5
MHz
0.05 MHz f_offset < 5.05
MHz
100 kHz
5 MHz f <
min(10 MHz,
fmax)
5.05 MHz f_offset <
min(10.05 MHz,
f_offsetmax)
-14 dBm 100 kHz
10 MHz f
fmax
10.05 MHz f_offset <
f_offsetmax
-16 dBm (Note 5) 100 kHz
TS 36.104 defines several limits: depending on
Channel bandwidth, additional regional limits and node B
limits category A or B for ITU defined regions
=> Several test setups are possible!
Narrow bandwidth
November 2012 | LTE measurements| 29
Operating band unwanted emissions
November 2012 | LTE measurements| 30
Unwanted emissions – spurious emission
The transmitter spurious emission limits apply from 9 kHz to 12.75 GHz,
excluding the frequency range from 10 MHz below the lowest frequency of the downlink
operating band up to 10 MHz above the highest frequency of the downlink operating band
Frequency range Maximum level Measurement
Bandwidth
Note
9kHz - 150kHz
-13 dBm
1 kHz Note 1
150kHz - 30MHz 10 kHz Note 1
30MHz - 1GHz 100 kHz Note 1
1GHz – 12.75 GHz 1 MHz Note 2
NOTE 1: Bandwidth as in ITU-R SM.329 [5] , s4.1
NOTE 2: Bandwidth as in ITU-R SM.329 [5] , s4.1. Upper frequency as in ITU-R SM.329 [5] , s2.5 table 1
Spurious emission limits, Category A
November 2012 | LTE measurements| 31
Spurious emissions – operating band excluded
November 2012 | LTE measurements| 32
Base station maximum power
BS
cabinet
Test port A Test port B
External
device
e.g.
TX filter
(if any)
External
PA
(if any)
Towards
antenna connector
Normal port for
measurements Port to be used for
measurements in case
external equipment is
used
In normal conditions, the base station maximum output power
shall remain within +2 dB and -2 dB of the rated output power
declared by the manufacturer.
November 2012 | LTE measurements| 33
LTE – DVB interference scenarios
For a BS declared to support Band 20 and to operate in geographic areas within the CEPT in which frequencies are allocated to broadcasting (DTT) service, the manufacturer shall additionally declare the following quantities associated with the applicable test conditions of Table 6.6.3.5.3-4 and information in annex G of [TS 36.104] :
PEM,N Declared emission level for channel N P10MHz Maximum output Power in 10 MHz
Adjacent channel leakage of
Basestation x into DTT channel N
is point of interest
November 2012 | LTE measurements| 34
Base station receiver test
70% of required throughput of FRC, Fixed Reference Channel
Example: Rx test, moving condition
November 2012 | LTE measurements| 35
Base station receiver test – HARQ multiplexing
UE sends PUSCH with alternating data
and data with multiplexed ACK
November 2012 | LTE measurements| 36
Base station test – power dynamics
BS under
Test
RF-
correc-
tion
FFT
2048 Per
subcarrier
Ampl.
/Phase
correction
Symbol
Detection /
decoding
100
RBs,
1200
sub
carr
CP-
remov
EVM
RETP
Synchronisation
time/frequency
Resource element Tx
power: Distinguish:
•OFDM symbol
•Reference symbol
November 2012 | LTE measurements| 37
[Time]
Downlink Power
[Power]
0 1 2 3 4 5 6 7 8 9 10 11 12 13
OFDM symbols
-50.00 dBm
PA = -4.77 dB
-54.77 dBm
-58.75 dBm
PB = 3 (-3.98 dB)
PDSCH power to RS, where NO reference
signals are present, is UE specific and
signaled by higher layers as PA.
Reference Signal:
Cell-specific
referenceSignalPower
(-60…+50dBm),
signaled in SIB Type 2 For PDSCH power in same
symbol as reference signal an
additional cell specific offset
is applied, that is signaled by
higher layers as PB.
PDCCH power
depending
on ρB/ρA
2011 ©
Ro
hd
e&
Sch
warz
RSBAPDSCH EPREEPRE /B B AP MIMO)for exeptions some(with AA P
RS EPRE = Reference Signal
Energy per Resource Element
Reference signal power = linear average of all Ref.
Symbols over whole channel bandwidth
November 2012 | LTE measurements| 38
Base station test – output power dynamics
Ref. Symbol, always on
OFDM Symbol not active!
OFDM Symbol active!
Measure avg OFDM
symbol power +
Compare active and
non-active case
PDSCH
# of 64QAM PDSCH PRBs within a slot for which EVM is measured
1 1 1 1 1 1
PRB PA = EA/ERS [dB] 0 0 0 0 0 0
# of PDSCH PRBs which are not allocated 5 14 24 49 74 99
PDSCH
# of 64QAM PDSCH PRBs within a slot for which EVM is measured
6 15 25 50 75 100
Test model:
E-TM3.1
All RB allocated
Test model:
E-TM2
Only 1 RB allocated
November 2012 | LTE measurements| 39
DL Modulation quality: Constellation diagram LTE downlink: several channels can be seen (example):
PDSCH with
16 QAM
PDCCH +
PBCH with
QPSK
S-SCH with
BPSK
CAZAC
Sequences,
Reference signals
November 2012 | LTE measurements| 40
LTE RF measurements on user equipment UEs
November 2012 | LTE measurements| 41
LTE Transmitter Measurements 1 Transmit power
1.1 UE Maximum Output Power
1.2 Maximum Power Reduction (MPR)
1.3 Additional Maximum Power Reduction (A-MPR)
1.4 Configured UE transmitted Output Power
2 Output Power Dynamics
2.1 Minimum Output Power
2.2 Transmit OFF power
2.3 ON/OFF time mask
2.3.1 General ON/OFF time mask
2.3.2 PRACH time mask
2.3.3 SRS time mask
2.4 Power Control
2.4.1 Power Control Absolute power tolerance
2.4.2 Power Control Relative power tolerance
2.4.3 Aggregate power control tolerance
3 Transmit signal quality
3.1 Frequency Error
3.2 Transmit modulation
3.2.1 Error Vector Magnitude (EVM)
3.2.2 Carrier leakage
3.2.3 In-band emissions for non allocated RB
3.2.4 EVM equalizer spectrum flatness
4 Output RF spectrum emissions
4.1 Occupied bandwidth
4.2 Out of band emission
4.2.1 Spectrum Emission Mask
4.2.2 Additional Spectrum Emission Mask
4.2.3 Adjacent Channel Leakage power Ratio
4.3 Spurious emissions
4.3.1 Transmitter Spurious emissions
4.3.2 Spurious emission band UE co-existence
4.3.3 Additional spurious emissions
5 Transmit intermodulation
November 2012 | LTE measurements| 42
UE Signal quality – symbolic structure of mobile radio tester MRT
RF correction FFT
TxRx
equalizer EVM meas. IDFT
Test equipment
Rx
…
…
…
…
…
…
Inband-
emmissions
l Carrier Frequency error
l EVM (Error Vector Magnitude)
l Origin offset + IQ offset
l Unwanted emissions, falling into non allocated resource blocks.
l Inband transmission
l Spectrum flatness
DUT
November 2012 | LTE measurements| 43
UL Power Control: Overview
UL-Power Control is a
combination of:
l Open-loop:
UE estimates the DL-Path-
loss and compensates it
for the UL
l Closed-loop:
in addition, the eNB
controls directly the UL-
Power through power-
control commands
transmitted on the DL
November 2012 | LTE measurements| 44
PUSCH power control
l Power level [dBm] of PUSCH is calculated every subframe i based on the following
formula out of TS 36.213
Dynamic offset (closed loop) Basic open-loop starting point
Maximum allowed UE power
in this particular cell,
but at maximum +23 dBm1)
Number of allocated
resource blocks (RB)
Combination of cell- and UE-specific
components configured by L3
Cell-specific
parameter
configured by L3
PUSCH transport
format
Transmit power for PUSCH
in subframe i in dBm
Power control
adjustment derived
from TPC command
received in subframe (i-4)
Downlink
path loss
estimate
Bandwidth factor
1) +23 dBm is maximum allowed power in LTE according to TS 36.101, corresponding to power class 3bis in WCDMA
MPR
November 2012 | LTE measurements| 45
„upper“ tolerance Pcmax definition
PCMAX_L– T(PCMAX_L) ≤ PCMAX ≤ PCMAX_H + T(PCMAX_H)
„corrected“ UE power
PCMAX_L = min{PEMAX_L, PUMAX } PCMAX_H = min{PEMAX_H, PPowerClass}
„lower“ tolerance
Max. power permitted
in cell,
considering bandwidth
confinement
Max. power for UE,
considering maximum
power reduction
Max. power
permitted in cell
Max. power for
UE
November 2012 | LTE measurements| 46
PCMAX_L– T(PCMAX_L) ≤ PCMAX ≤ PCMAX_H + T(PCMAX_H),
l PEMAX_L is the maximum allowed power for this particular radio cell
configured by higher layers and corresponds to P-MAX information
element (IE) provided in SIB Type1
l
l PEMAX_L is reduced by 1.5 dB when the transmission BW is confined within
FUL_low and FUL_low+4 MHz or FUL_high – 4 MHz and FUL_high,
Pcmax definition
lPCMAX_L = min{PEMAX_L , PUMAX },
FUL_low FUL_high
PPowerClass +
2dB
PPowerClass - 2dB 23dBm
FUL_high- 4MHz
-1.5dB -1.5dB
November 2012 | LTE measurements| 47
PCMAX_L– T(PCMAX_L) ≤ PCMAX ≤ PCMAX_H + T(PCMAX_H),
l PUMAX corresponds to maximum power (depending on power class,
taking into account Maximum Power Reduction MPR and additional
A-MPR
Pcmax definition
PCMAX_L = min{PEMAX_L , PUMAX },
UE power class
= 23dBm ±2 dB Network may signal
bandwidth restriction
NS_0x
UE may decide to
reduce power
November 2012 | LTE measurements| 48
UE Maximum Power Reduction
UE transmits
at maximum power, maximum allowed
TX power reduction is given as
Modulation Channel bandwidth / Transmission bandwidth configuration
[RB]
MPR (dB)
1.4
MHz
3.0
MHz
5
MHz
10
MHz
15
MHz
20
MHz
QPSK > 5 > 4 > 8 > 12 > 16 > 18 ≤ 1
16 QAM ≤ 5 ≤ 4 ≤ 8 ≤ 12 ≤ 16 ≤ 18 ≤ 1
16 QAM Full > 5 > 4 > 8 > 12 > 16 > 18 ≤ 2
Higher order modulation schemes require
more dynamic -> UE will slightly repeal its
confinement for maximum power
November 2012 | LTE measurements| 49
UE Additional Maximum Power Reduction A-MPR
Network
Signaling
value
Requirements
(sub-clause)
E-UTRA Band Channel
Bandwidth
(MHz)
Resource
Blocks
A-MPR (dB)
NS_01 NA NA NA NA NA
NS_03
6.6.2.2.3.1 2,4,35,36 3 >5 ≤ 1
6.6.2.2.3.1 2,4,10,35,36 5 >6 ≤ 1
6.6.2.2.3.1 2,4,10,35,36 10 >6 ≤ 1
6.6.2.2.3.1 2,4,10,35,36 15 >8 ≤ 1
6.6.2.2.3.1 2,4,10,35,36 20 >10 ≤ 1
NS_04 6.6.2.2.3.2 TBD TBD TBD TBD
NS_05 6.6.3.3.3.1 1 10,15,20 ≥ 50 for QPSK ≤ 1
NS_06 6.6.2.2.3.3 12, 13, 14, 17 1.4, 3, 5, 10 n/a n/a
NS_07 6.6.2.2.3.3
6.6.3.3.3.2 13 10 Table 6.2.4.3-2
Table
6.2.4.3-2
NS_08 6.6.3.3.3.3 19 10, 15
> 29 ≤ 1
> 39 ≤ 2
> 44 ≤ 3
[NS_09] 6.6.3.3.3.4 21 TBD TBD TBD
..
NS_32 - - - - -
Additional maximum
power reduction
requirements can be
signaled by the
network as NS value
in SIB2 (IE AdditionalSpectrumEmission)
November 2012 | LTE measurements| 50
PUSCH power control Transmit output power ( PUMAX), cont’d.
l In case of EUTRA Band 13 depending on RB allocation as well as
number of contiguously allocated RB different A-MPR needs to be
considered.
Network
Signalling
Value
Requiremen
ts
(sub-clause)
E-UTRA
Band
Channel
bandwidth
(MHz)
Resources
Blocks
A-MPR
(dB)
… … … … … …
NS_07 6.6.2.2.3
6.6.3.3.2 13 10
Table
6.2.4
-2
Table
6.2.4
-2
… … … … … …
Region A Region B Region C
RBStart 0 – 12 13 – 18 19 – 42 43 – 49
LCRB [RBs] 6 – 8 1 – 5 to 9 – 50 ≥8 ≥18 ≤2
A-MPR [dB] 8 12 12 6 3
Indicates the lowest RB
index of transmitted
resource blocks
Defines the length of a
contiguous RB allocation
DL UL
756 746 787 777
3GPP Band 13
November 2012 | LTE measurements| 51
PCMAX_L– T(PCMAX_L) ≤ PCMAX ≤ PCMAX_H + T(PCMAX_H)
Pcmax definition – tolerance values
PCMAx
(dBm)
Tolerance
T(PCMAX) (dB)
21 ≤ PCMAX ≤ 23 2.0
20 ≤ PCMAX < 21 2.5
19 ≤ PCMAX < 20 3.5
18 ≤ PCMAX < 19 4.0
13 ≤ PCMAX < 18 5.0
8 ≤ PCMAX < 13 6.0
-40 ≤ PCMAX < 8 7.0
Tolerance is
depending on
power levels
November 2012 | LTE measurements| 52
Pcmax definition – tolerance values
l PEMAX_H is the maximum allowed power for this particular radio
cell configured by higher layers and corresponds to P-MAX
information element (IE) provided in SIB Type 1
PCMAX_L– T(PCMAX_L) ≤ PCMAX ≤ PCMAX_H + T(PCMAX_H)
PCMAX_H = min{PEMAX_H , PPowerClass },
UE power class
= 23dBm ±2 dB
November 2012 | LTE measurements| 53
Pcmax definition – tolerance values
l PPowerClass. There is just one power class specified for LTE,
corresponding to power class 3bis in WCDMA with +23 dBm ± 2dB,
MPR and A-MPR are not taken into account,
PCMAX_L– T(PCMAX_L) ≤ PCMAX ≤ PCMAX_H + T(PCMAX_H)
PCMAX_H = min{PEMAX_H , PPowerClass },
EUTRA
band
Class 1
(dB
m)
Tolerance
(dB)
Class 2
(dBm)
Tolerance
(dB)
Class 3
(dBm
)
Tolerance (dB) Class 4
(dBm)
Tolerance (dB)
1 23 ±2
2 23 ±22
… 23 ±22
40 23 ±2
November 2012 | LTE measurements| 54
Pcmax value for power control - analogies
Maximum speed = 280 km/h
=PPowerClass
=PEMAX_H =PEMAX_L =PUMAX
Under those conditions,
I shall drive more carefully!
Not going to the max seed!
-> speed reduction
PCMAX_L– T(PCMAX_L) ≤ PCMAX ≤ PCMAX_H + T(PCMAX_H)
PCMAX_L = min{PEMAX_L, PUMAX } PCMAX_H = min{PEMAX_H, PPowerClass}
November 2012 | LTE measurements| 55
LTE RF Testing: UE Maximum Power
UE transmits
with 23dBm ±2 dB
QPSK modulation is used. All channel bandwidths are
tested separately. Max power is for all band classes
Test is performed for varios uplink allocations
November 2012 | LTE measurements| 56
Resource Blocks number and maximum RF power
One active resource block
(RB) provides maximum
absolute RF power RF p
ow
er
Frequency
RF p
ow
er
Frequency
More RB’s in use will be at
lower RF power in order to
create same integrated
power
1 active resource block (RB),
Nominal band width 10 MHz = 50 RB’s
RF p
ow
er
Frequency
Additionally, MPR (Max.
Power Reduction) and A-
MPR are defined MPR
November 2012 | LTE measurements| 57
UE Maximum Output Power – Test Configuration Initial Conditions
Test Environment as specified in TS 36.508 subclause 4.1 Normal, TL/VL, TL/VH, TH/VL, TH/VH
Test Frequencies as specified in TS 36.508 subclause 4.3.1 Low range, Mid range, High range
Test Channel Bandwidths as specified in TS 36.508 subclause 4.3.1 Lowest, 5MHz, Highest
Test Parameters for Channel Bandwidths
Downlink Configuration Uplink Configuration
Ch BW N/A for Max UE output power testing Mod’n RB allocation
FDD TDD
1.4MHz QPSK 1 1
1.4MHz QPSK 5 5
3MHz QPSK 1 1
3MHz QPSK 4 4
5MHz QPSK 1 1
5MHz QPSK 8 8
10MHz QPSK 1 1
10MHz QPSK 12 12
15MHz QPSK 1 1
15MHz QPSK 16 16
20MHz QPSK 1 1
20MHz QPSK 18 18
Temperature/Voltage
high/low
November 2012 | LTE measurements| 58
UE maximum power
FUL_low FUL_high
PPowerClass + 2dB
PPowerClass - 2dB
maximum output
power for any
transmission bandwidth
within the channel bandwidth
23dBm
November 2012 | LTE measurements| 59
UE maximum power – careful at band edge!
FUL_low FUL_high
PPowerClass + 2dB
PPowerClass - 2dB
23dBm
FUL_high- 4MHz FUL_low+4MHz
For transmission bandwidths confined within FUL_low and FUL_low + 4 MHz or
FUL_high – 4 MHz and FUL_high, the maximum output power requirement is relaxed
by reducing the lower tolerance limit by 1.5 dB
-1.5dB -1.5dB
November 2012 | LTE measurements| 60
UE maximum power - examples
FUL_low FUL_high
PPowerClass + 2dB
PPowerClass - 2dB
23dBm
Example 1: No maximum power reduction by higher layers
PCMAX_L– T(PCMAX_L) ≤ PCMAX ≤ PCMAX_H + T(PCMAX_H)
PCMAX_L = min{PEMAX_L, PUMAX } PCMAX_H = min{PEMAX_H, PPowerClass}
Max. power permitted in cell,
considering bandwidth
confinement
Max. power for UE,
considering maximum power
reduction
Max. power permitted in
cell Max. power for UE
PEMAX_L = none PUMAX = power class 3 = +23 dBm
PEMAX_H = none PPowerClass = power class 3 = +23 dBm 25dBm
21dBm
T(PCMAX_L) = T(PCMAX_H)=2dB
November 2012 | LTE measurements| 61
UE maximum power - examples
FUL_low FUL_high
PCMAX_H + 7dB
PCMAX_L - 7dB
0 dBm
Example 2: max cell power = 0 dBm + band edge maximum power reduction
PCMAX_L– T(PCMAX_L) ≤ PCMAX ≤ PCMAX_H + T(PCMAX_H)
PCMAX_L = min{PEMAX_L, PUMAX } PCMAX_H = min{PEMAX_H, PPowerClass}
PEMAX_L = 0dBm -1.5 dB relaxation = -1.5dBm
PUMAX = power class 3 – band relaxation = +21.5 dBm
+7dBm
-8.5dBm
T(PCMAX_L) = T(PCMAX_H)=7dB
PEMAX_H = 0 dBm
PPowerClass = power class 3 = +23 dBm
PCMAX_L=-1.5dBm PCMAX_H=0 dBm
FUL_low+4MHz
November 2012 | LTE measurements| 62
UE maximum power - examples
RB start = 13 FUL_high
PCMAX_H +2dB
PCMAX_L - 6dB
23 dBm
Example 3: Band 13 with NS_07 signalled ( = A-MPR). No Max Power restriction
16 QAM, 12 Resource blocks and RB start = 13. Bandwidth = 10 MHz
PCMAX_L– T(PCMAX_L) ≤ PCMAX ≤ PCMAX_H + T(PCMAX_H)
PCMAX_L = min{PEMAX_L, PUMAX } PCMAX_H = min{PEMAX_H, PPowerClass}
PEMAX_L = none
PUMAX = power class 3 – MPR – A.MPR = +10 dBm
+25dBm
4 dBm
T(PCMAX_L) = 6 dB
T(PCMAX_H)=2dB
PEMAX_H = none
PPowerClass = power class 3 = +23 dBm
PCMAX_L=10 dBm PCMAX_H=23 dBm
12 Resource blocks
MPR = 1dB, A-MPR = 12 dB, no band edge relaxation
November 2012 | LTE measurements| 63
UE maximum power - examples
FUL_low FUL_high
PCMAX_H + 2dB
PCMAX_L – 2 dB
23 dBm
Example 4: band edge power relaxation – no higher layer reduction signalled
QPSK, 15 RBs allocated, Band 2, RB allocated at band edge
PCMAX_L– T(PCMAX_L) ≤ PCMAX ≤ PCMAX_H + T(PCMAX_H)
PCMAX_L = min{PEMAX_L, PUMAX } PCMAX_H = min{PEMAX_H, PPowerClass}
PEMAX_L =none
PUMAX = power class 3 – MPR-A-MPR-band relaxation
= 23-1-1-1.5=+19.5 dBm
+25 dBm
+16 dBm
PEMAX_H = none
PPowerClass = power class 3 = +23 dBm
PCMAX_L=19.5dBm
PCMAX_H= 23 dBm
FUL_low+4MHz
MPR = 1dB, A-MPR = 1 dB, band edge relaxation of 1.5dB
T(PCMAX_L) = 3.5 dB
T(PCMAX_H)=2dB
PCMAX_L – 3.5 dB
November 2012 | LTE measurements| 64
LTE RF Testing: UE Minimum Power
UE transmits
with -40dBm
All channel bandwidths are tested separately.
Minimum power is for all band classes < -39 dBm
November 2012 | LTE measurements| 65
LTE RF Testing: UE Off Power
The transmit OFF power is defined as the mean power in a duration of at least one
sub-frame (1ms) excluding any transient periods. The transmit OFF power shall not
exceed the values specified in table below
Channel bandwidth / Minimum output power / measurement bandwidth
1.4
MHz
3.0
MHz
5
MHz
10
MHz
15
MHz
20
MHz
Transmit OFF power -50 dBm
Measurement
bandwidth 1.08 MHz 2.7 MHz 4.5 MHz 9.0 MHz 13.5 MHz 18 MHz
November 2012 | LTE measurements| 66
Power Control Related test items
l Absolute Power Control Tolerance -- PUSCH open loop
power control
l Relative Power Control Tolerance – PUSCH relative power
control, including both power ramping and power change due
to Ressource block allocation change or TPC commands
l Aggregate Power Control – PUSCH and PUCCH power
control ability when RB changes every subframe
November 2012 | LTE measurements| 67
Absolute Power Control Tolerance
l The purpose of this test is to verify the UE transmitter’s
ability to set its initial output power to a specific value at the
start of a contiguous transmission or non-contiguous
transmission with a long transmission gap.
November 2012 | LTE measurements| 68
Power Control - Absolute Power Tolerance
l …. ability to set initial output power to a specific value at the start of a
contiguous transmission or non-contiguous transmission with a long
transmission gap (>20ms).
l Set p0-NominalPUSCH to -105 (test point 1) and -93 (test point 2)
l Test requirement example for test point 1:
Channel bandwidth / expected output power (dBm)
1.4
MHz
3.0
MHz
5
MHz
10
MHz
15
MHz
20
MHz
Expected Measured
power Normal
conditions
-14.8 ±
10.0
-10.8 ±
10.0
-8.6 ±
10.0
-5.6 ±
10.0
-3.9 ±
10.0
-2.6 ±
10.0
Expected Measured
power Extreme
conditions
-14.8 ±
13.0
-10.8 ±
13.0
-8.6 ±
13.0
-5.6 ±
13.0
-3.9 ±
13.0
-2.6 ±
13.0
November 2012 | LTE measurements| 69
Configured UE transmitted Output Power
Test: set P-Max to -10, 10 and 15 dBm, measure PCMAX
IE P-Max (SIB1) = PEMAX
Channel bandwidth / maximum output power
1.4
MHz
3.0
MHz
5
MHz
10
MHz
15
MHz
20
MHz
PCMAX test point 1 -10 dBm ± 7.7
PCMAX test point 2 10 dBm ± 6.7
PCMAX test point 3 15 dBm ± 5.7
To verify that UE follows rules sent via
system information, SIB
November 2012 | LTE measurements| 70
LTE Power versus time
)}())(()())((log10,min{)( TFO_PUSCHPUSCH10MAXPUSCH ifiTFPLjPiMPiP
Bandwidth allocation TPC commands Given by higher layers
or not used
RB allocation
is main source for
power change
Not scheduled
Resource block
November 2012 | LTE measurements| 71
2
Accumulative TPC commands
TPC Command Field
In DCI format 0/3
Accumulated
[dB]
0 -1
1 0
2 1
3 3
PUSCH
minimum
power in LTE
November 2012 | LTE measurements| 72
Absolute TPC commands
TPC Command Field
In DCI format 0/3
Absolute [dB]
only DCI format 0
0 -4
1 -1
2 1
3 4
PUSCH
Pm
)}())(()())((log10,min{)( TFO_PUSCHPUSCH10MAXPUSCH ifiTFPLjPiMPiP
-4 -1
November 2012 | LTE measurements| 73
Relative Power Control
0 .. 9 sub-frame# 1 2 3 4 radio frame
0 .. 9 sub-frame# 1 2 3 4 radio frame
RB change
RB change
Power pattern A
Power pattern C
0 .. 9 sub-frame# 1 2 3 4 radio frame
RB change
Power pattern B
l The purpose of this test is to verify
the ability of the UE transmitter to set
its output power relatively to the
power in a target sub-frame, relatively
to the power of the most recently
transmitted reference sub-frame, if the
transmission gap between these sub-
frames is ≤ 20 ms.
November 2012 | LTE measurements| 74
Power Control – Relative Power Tolerance
l …. ability to set output power relative to the power in a target sub
frame, relative to the power of the most recently transmitted
reference sub-frame, if the transmission gap between these
sub-frames is ≤ 20 ms.
November 2012 | LTE measurements| 75
Power Control – Relative Power Tolerance
l Various power ramping patterns are defined
ramping up
ramping down
alternating
November 2012 | LTE measurements| 76
UE power measurements – relative power change
Power step P
(Up or down)
[dB]
All combinations of
PUSCH and
PUCCH
transitions [dB]
All combinations of
PUSCH/PUCCH
and SRS
transitions
between sub-
frames [dB]
PRACH [dB]
ΔP < 2 ±2.5 (Note 3) ±3.0 ±2.5
2 ≤ ΔP < 3 ±3.0 ±4.0 ±3.0
3 ≤ ΔP < 4 ±3.5 ±5.0 ±3.5
4 ≤ ΔP ≤ 10 ±4.0 ±6.0 ±4.0
10 ≤ ΔP < 15 ±5.0 ±8.0 ±5.0
15 ≤ ΔP ±6.0 ±9.0 ±6.0
P
time
Power tolerance relative given by table
November 2012 | LTE measurements| 77
UE power measurements – relative power change
Power
FDD test patterns
0 1 9 sub-frame#
Power
TDD test patterns
0 2 3 7 8 9 sub-frame#
Sub-test Uplink RB allocation TPC command Expected power
step size
(Up or
down)
Power step size
range (Up or
down)
PUSCH/
ΔP [dB] ΔP [dB] [dB]
A Fixed = 25 Alternating TPC =
+/-1dB 1 ΔP < 2 1 ± (1.7)
B Alternating 10 and 18 TPC=0dB 2.55 2 ≤ ΔP < 3 2.55 ± (3.7)
C Alternating 10 and 24 TPC=0dB 3.80 3 ≤ ΔP < 4 3.80 ± (42.)
D Alternating 2 and 8 TPC=0dB 6.02 4 ≤ ΔP < 10 6.02 ± (4.7)
E Alternating 1 and 25 TPC=0dB 13.98 10 ≤ ΔP < 15 13.98 ± (5.7)
F Alternating 1 and 50 TPC=0dB 16.99 15 ≤ ΔP 16.99 ± (6.7)
test for
each
bandwidth,
here 10MHz
November 2012 | LTE measurements| 78
UE aggregate power tolerance
Aggregate power control tolerance is the ability of a UE to maintain its power in
non-contiguous transmission within 21 ms in response to 0 dB TPC commands
TPC command UL channel Aggregate power tolerance within 21 ms
0 dB PUCCH ±2.5 dB
0 dB PUSCH ±3.5 dB
Note:
1. The UE transmission gap is 4 ms. TPC command is transmitted via PDCCH 4 subframes preceding
each PUCCH/PUSCH transmission.
P
Time = 21 milliseconds
UE power with
TPC = 0
Tolerated UE power
deviation
November 2012 | LTE measurements| 79
Aggregate Power Control
l The purpose of this test is to verify the UE’s ability to
maintain its power level during a non-contiguous
transmission within 21 ms in response to 0 dB TPC
commands with respect to the first UE transmission, when
the power control parameters specified in TS 36.213 are
constant.
l Both PUSCH mode and PUCCH mode need to be tested
Power
FDD test patterns
0 5 0 5 0
sub-frame#
Power
TDD test patterns
3 8 3 8 3
sub-frame#
November 2012 | LTE measurements| 80
UE aggregate power tolerance
Power
FDD test patterns
0 5 0 5 0
sub-frame#
Power
TDD test patterns
3 8 3 8 3
sub-frame#
Test performed with scheduling gap of 4 subframes
November 2012 | LTE measurements| 81
UE power measurement – timing masks
End of OFF power
20µs 20µs
Transient period Transient period
Start of OFF power
Start of ON power
requirement
Start Sub-frame End sub-frame
End of ON power
requirement
* The OFF power requirements does not
apply for DTX and measurement gaps
Timing definition OFF – ON commands
Timing definition ON – OFF commands
November 2012 | LTE measurements| 82
Power dynamics
PUSCH = ON PUSCH = OFF PUSCH = OFF time
Please note: scheduling cadence for power dynamics
November 2012 | LTE measurements| 83
General ON/OFF time mask Measured subframe = 2
UL/DL Scheduling should be configured properly.
TDD Issues: - Special Subframe
Configuration
- >off power before is
highter than off
power after
- <> tune down DL
power
November 2012 | LTE measurements| 84
PRACH time mask
ON power requirement
requirement
20µs 20µs
Transient period Transient period
PRACH
End of OFF power Start of OFF power
requirement
PRACH
preamble
format
Measurement
period (ms)
0 0.9031
1 1.4844
2 1.8031
3 2.2844
4 0.1479
Channel bandwidth / Output Power [dBm] / measurement
bandwidth
1.4
MHz
3.0
MHz
5
MHz
10
MHz
15
MHz
20
MHz
Transmit OFF
power -48.5 dBm
Transmission OFF
Measurement
bandwidth
1.08 MHz 2.7 MHz 4.5 MHz 9.0 MHz 13.5 MHz 18 MHz
Expected PRACH
Transmission ON
Measured power
-1± 7.5 -1 ± 7.5 -1 ± 7.5 -1 ± 7.5 -1 ± 7.5 -1 ± 7.5
November 2012 | LTE measurements| 85
UE power measurement – PRACH timing mask
ON power requirement
requirement
20µs 20µs
Transient period Transient period
PRACH
End of OFF power Start of OFF power
requirement
PRACH preamble format Measurement period (ms)
0 0.9031
1 1.4844
2 1.8031
3 2.2844
4 0.1479
November 2012 | LTE measurements| 86
PRACH measurements
For PRACH
you have to
set a trigger Reminder:
PRACH is
CAZAC
sequence
November 2012 | LTE measurements| 87
PRACH measurement: constellation diagram
Reminder:
PRACH is
CAZAC
sequence
November 2012 | LTE measurements| 88
PRACH measurement: power dynamics
November 2012 | LTE measurements| 89
Sounding Reference Signal Time Mask
November 2012 | LTE measurements| 90
UE power measurement – SRS timing mask
requirement
20µs 20µs
Transient period Transient period
End of OFF
power requirement
SRS
SRS ON power
requirement
Start of OFF power
End of OFF
20µs 20µs 20µs 20µs
* Transient period is only specifed in the case of frequency hopping or a power change between SRS symbols
*Transient periodTransient period
SRS SRS
requirement
Transient period
Start of OFF power
power requirement
SRS ON power
requirement
SRS ON power
requirement
Single Sounding
Reference Symbol
Double Sounding
Reference Symbol
November 2012 | LTE measurements| 91
UE power measurement – Subframe / slot boundary
20µs 20µs 20µs 20µs 20µs 20µs
Transient period Transient period Transient period
Start of N+1 power
requirement
End of N+1 power
requirement
N+1 Sub-frame
Sloti Sloti+1
N0 Sub-frame N+2 Sub-frame
Periods where power changes may occur
If intra-slot hopping is enabled
November 2012 | LTE measurements| 92
Tx power aspects RB power = Ressource Block Power, power of 1 RB TX power = integrated power of all assigned RBs
November 2012 | LTE measurements| 93
Resource allocation versus time
PUSCH allocation, different #RB and RB offset
PUCCH
allocation
No resource
scheduled
November 2012 | LTE measurements| 94
TTI based scheduling
November 2012 | LTE measurements| 95
LTE scheduling impact on power versus time
TTI based scheduling.
Different RB allocation
Impact
on UE
power
November 2012 | LTE measurements| 96
Transmit signal quality
November 2012 | LTE measurements| 97
Transmit signal quality – carrier leakage
f
Parameters Relative Limit (dBc)
Output power >0 dBm -25
-30 dBm ≤ Output power ≤0 dBm -20
-40 dBm Output power < -30 dBm -10
Carrier leakage (The IQ origin offset) is an additive sinusoid waveform
that has the same frequency as the modulated waveform carrier frequency.
Frequency error
fc Fc+ε
November 2012 | LTE measurements| 98
Frequency Error
…. ability of both the receiver and the transmitter to process frequencies
correctly…
The 20 frequency error Δf results must fulfil this test requirement:
|Δf| ≤ (0.1 PPM + 15 Hz)
observed over a period of one time slot (0.5ms)
November 2012 | LTE measurements| 99
Impact on Tx modulation accuracy evaluation
l 3 modulation accuracy requirements
l EVM for the allocated RBs
l LO leakage for the centred RBs ! LO spread on all RBs
l I/Q imbalance in the image RBs
frequency
RF carrier
RB0 RB1 RB2 RB3 RB4 RB5
level
signal
noise
LO leakage
I/Q imbalance
EVM
November 2012 | LTE measurements| 100
Inband emissions
Used
allocation <
½ channel
bandwidth
channel bandwidth
3 types of inband emissions: general, DC and IQ image
November 2012 | LTE measurements| 101
Carrier Leakage Carrier leakage (the I/Q origin offset) is a form of interference caused by crosstalk or DC offset.
It expresses itself as an un-modulated sine wave with the carrier frequency.
I/Q origin offset interferes with the center sub carriers of the UE under test.
The purpose of this test is to evaluate the UE transmitter to verify its modulation quality in
terms of carrier leakage.
DC carrier leakage
due to IQ offset
LO
Leakage
Parameters Relative
Limit (dBc)
Output power >0 dBm -25
-30 dBm ≤ Output power ≤0 dBm -20
-40 dBm Output power < -30 dBm -10
November 2012 | LTE measurements| 102
Inband emmission – error cases DC carrier leakage
due to IQ offset
November 2012 | LTE measurements| 103
Inband emmission – error cases Inband image
due to IQ inbalance
November 2012 | LTE measurements| 104
Inband emmission – error cases Inband image
due to IQ inbalance
November 2012 | LTE measurements| 105
DC leakage and IQ imbalance in real world …
November 2012 | LTE measurements| 106
UL Modulation quality: Constellation diagram LTE PUSCH uses
QPSK, 16QAM
and 64 QAM (optional)
modulation schemes.
In UL there is only 1 scheme
allowed per subframe
November 2012 | LTE measurements| 107
Error Vector Magnitude, EVM
Error Vector
Q
I
Ideal (Reference) Signal
Measured
Signal
Φ
Phase Error (IQ error phase)
Magnitude Error (IQ error magnitude)
Σ
Demodulator Ideal
Modulator Input Signal
-
+
011001…
Reference Waveform
Measured Waveform
Difference Signal
November 2012 | LTE measurements| 108
Error Vector Magnitude, EVM 7 symbols / slot
0 1 2 3 4 5 6 0 1 2 3 4 5 6 0 1 2 3 4 5 6 0 1 2 3 4 5 6 time
frequency
PUSCH symbol
Demodulation Reference
symbol, DMRS
Parameter
Unit Level
QPSK % 17.5
16QAM % 12.5
64QAM % [tbd]
Limit values
November 2012 | LTE measurements| 109
Error Vector Magnitude, EVM
Cyclic
prefix
OFDM
Symbol
Part equal
to CP
1 SC-FDMA symbol, including Cyclic Prefix, CP CP center
FFT Window size
FFT window size depends
on channel bandwidth and
extended/normal CP length
November 2012 | LTE measurements| 110
Error Vector Magnitude, EVM
Cyclic
prefix
OFDM
Symbol
Part equal
to CP
1 SC-FDMA symbol, including Cyclic Prefix, CP CP center
FFT Window size
cpN
Cyclic prefix length
cpNChannel
Bandwidt
h MHz
for symbol 0 for symbols 1
to 6
Nominal
FFT size
Cyclic prefix
for symbols
1 to 6 in FFT
samples
EVM
window
length
W
Ratio of
W to CP
for
symbols 1
to 6*
1.4
160 144
128 9 [5] [55.6]
3 256 18 [12] [66.7]
5 512 36 [32] [88.9]
10 1024 72 [66] [91.7]
15 1536 108 [102] [94.4]
20 2048 144 [136] [94.4]
* Note: These percentages are informative and apply to symbols 1 through 6. Symbol 0 has a
longer CP and therefore a lower percentage.
FFT window size depends on channel bandwidth
and extended/normal CP length
Table from TS 36.101 for normal CP
FFT window does
not capture the
full length: OFDM
Symbol + CP
November 2012 | LTE measurements| 111
EVM measurement according to Spec
l Applies to PUSCH, PUCCH
and PRACH
l PUSCH and PUCCH UL Tx
Pwer
l @ Max & -36.8 dBm
l PRACH UL Tx Power
l FDD: @ -31 dBm & 14 dBm*
l TDD: @ -39 dBm & 6 dBm
Test Parameters for Channel Bandwidths
Downlink
Configuration
Uplink Configuration
Ch BW N/A for PUSCH EVM
testing
Mod’n RB allocation
FDD TDD
1.4MHz QPSK 6 6
1.4MHz QPSK 1 1
1.4MHz 16QAM 6 6
1.4MHz 16QAM 1 1
3MHz QPSK 15 15
3MHz QPSK 4 4
3MHz 16QAM 15 15
3MHz 16QAM 4 4
5MHz QPSK 25 25
5MHz QPSK 8 8
5MHz 16QAM 25 25
5MHz 16QAM 8 8
10MHz QPSK 50 50
10MHz QPSK 12 12
10MHz 16QAM 50
(Note 3)
50
(Note 3)
10MHz 16QAM 12 12
15MHz QPSK 75 75
15MHz QPSK 16 16
15MHz 16QAM 75
(Note 3)
75
(Note 3)
15MHz 16QAM 16 16
20MHz QPSK 100 100
20MHz QPSK 18 18
20MHz 16QAM 100
(Note 3)
100
(Note 3)
20MHz 16QAM 18 18
Note 1: Test Channel Bandwidths are checked separately for each E-
UTRA band, which applicable channel bandwidths are specified in Table
5.4.2.1-1.
Note 2: For partial RB allocation, the starting resource block shall be
RB #0 and RB# (max+1 - RB allocation) of the channel bandwidth.
Note 3: Applies only for UE-Categories 2-5
* 20MHz, we can only reach 13 dBm
November 2012 | LTE measurements| 112
Cyclic prefix aspects
OFDM symbol is periodic!
Cyclic prefix does not provoque
phase shift
OFDM symbol n OFDM symbol n-1
We can observe a phase shift
Content is
different in each
OFDM symbol
CP CP
part CP
CP
part
November 2012 | LTE measurements| 113
Time windowing
Cyclic
prefix
OFDM
Symbol
Part equal
to CP
1 SC-FDMA symbol, including Cyclic Prefix, CP
Cyclic
prefix
OFDM
Symbol
Part equal
to CP
1 SC-FDMA symbol, including Cyclic Prefix, CP
Continuous phase shift
Difference in phase shift
Phase shift between SC-FDMA
symbols will cause side lobes
in spectrum display!
November 2012 | LTE measurements| 114
Time windowing
Cyclic
prefix
OFDM
Symbol
Part equal
to CP
Cyclic
prefix
OFDM
Symbol
Part equal
to CP
Continuous phase shift Difference in phase shift
Tx Time window Tx Time window
Tx time window creates
some kind of clipping in
symbol transitions
Tx time window can be used
to shape the Tx spectrum in
a more steep way, but ….
November 2012 | LTE measurements| 115
Time windowing
Cyclic
prefix
OFDM
Symbol
Part equal
to CP
Cyclic
prefix
OFDM
Symbol
Part equal
to CP
Continuous phase shift Difference in phase shift
Tx Time window Tx Time window
Tx time window creates
some kind of clipping in
symbol transitions
Tx time window will create
a higher Error Vector Magnitude!
Here the Tx time window of 5µsec causes
Some mismatch between the 2 EVM
Measurements of the first SC-FDMA symbol
November 2012 | LTE measurements| 116
EVM vs. subcarrier
f
f0 f2 f1 f3
Nominal subcarriers
Each subcarrier
Modulated with
e.g. QPSK
. . . .
Integration of all
Error Vectors to
Display EVM curve
Error vector
Error vector
Note: simplified figure: in reality you
compare the waveforms due to SC-FDMA
November 2012 | LTE measurements| 117
EVM vs. subcarrier
November 2012 | LTE measurements| 118
EVM Equalizer Spectrum Flatness
2
2
*12
|)((|
|))((|*12
1
log*10)(fECA
fECAN
fP RBNRB
f
f0 f2 f1 f3
Nominal subcarriers
Subcarriers before
equalization
Amplitude Equalizer
coefficients
Integration of all
amplitude equalizer
coefficients to display
spectral flatness curve
The EVM equalizer spectrum flatness is defined as the variation in dB of the equalizer coefficients
generated by the EVM measurement process.
The EVM equalizer spectrum flatness requirement does not limit the correction applied to the signal
in the EVM measurement process but for the EVM result to be valid,
the equalizer correction that was applied must meet the
EVM equalizer spectral flatness minimum requirements.
November 2012 | LTE measurements| 119
Equalization
A(f)
f
Equalizer tries to
set same power level for
all subcarriers
1-tap equalization =
Interpreting the frequency
Selectivity as scalar factor
1-tap equalization =
Calculating scalar to
amplify or attenuate
November 2012 | LTE measurements| 120
Spectrum flatness calculation
A(f)
f
Equalizer tries to
set same power level for
all subcarriers
1-tap equalization =
Interpreting the frequency
Selectivity as scalar factor
1-tap equalization =
Calculating scalar to
amplify or attenuate 2
2
*12
|)((|
|))((|*12
1
log*10)(fECA
fECAN
fP RBNRB
November 2012 | LTE measurements| 121
Spectral flatness
November 2012 | LTE measurements| 122
Spectrum Flatness
Frequency Range
Maximum Ripple [dB]
FUL_Meas – FUL_Low ≥ 3 MHz and FUL_High – FUL_Meas ≥ 3 MHz
(Range 1)
5.4 (p-p)
FUL_Meas – FUL_Low < 3 MHz or FUL_High – FUL_Meas < 3 MHz
(Range 2)
9.4 (p-p)
Note 1: FUL_Meas refers to the sub-carrier frequency for which the equalizer
coefficient is evaluated
Note 2: FUL_Low and FUL_High refer to each E-UTRA frequency band specified in
Table 5.2-1
FUL_High FUL_High – 3(5) MHz
< 5.4(5.4)
dBp-p
Range 1 Range 2
max(Range 1)-min(Range 2) < 6.4(7.4) dB max(Range 2)-min(Range 1) < 8.4(11.4) dB < 9.4(13.4) dBp-p
November 2012 | LTE measurements| 123
Harmonics, parasitic
emissions, intermodulation
and frequency conversion
from
modulation
process
Output RF Spectrum Emissions
Spurious domain
RB
Channel bandwidth Spurious domain
ΔfOOB
ΔfOOB
E-UTRA Band
Worst case:
Resource Blocks allocated at
channel edge
Spectrum Emission Mask – SEM
-> measurement point by point (RBW)
Adjacent Channel Leakage Ratio – ACLR
-> integration (channel bandwidth)
occupied
bandwidth
Out-of-band emissions Spurious Emissions
November 2012 | LTE measurements| 124
Impact on SEM definition
l SEM defined for worst case scenario: RBs allocated at channel edge
l OOB emission scales with channel BW
>> a SEM per channel BW configuration
Channel
bandwidth
BWChannel
[MHz]
1.4 3 5 10 15 20
Length of OOB
domain on one
side [MHz]
5 6 10 15 20 25
5 MHz QPSK LTE Tx spectrum : +23.0 dBm / +22.0 dBm
-60
-50
-40
-30
-20
-10
0
10
20
30
-10 -9 -8 -7 -6 -5 -4 -3 -2 -1 0 1 2 3 4
offset (MHz)
level (d
Bm
/100kH
z)
1 RB MPR 0dB
5 RBs MPR 0dB
6 RBs MPR 0dB
7 RBs MPR 0dB
8 RBs MPR 0dB
9 RBs MPR 1dB
10 RBs MPR 1dB
11 RBs MPR 1dB
12 RBs MPR 1dB
13 RBs MPR 1dB
14 RBs MPR 1dB
15 RBs MPR 1dB
16 RBs MPR 1dB
18 RBs MPR 1dB
20 RBs MPR 1dB
25 RBs MPR 1dB
November 2012 | LTE measurements| 125
Adjacent Channel Leakage Ratio - ACLR
l UTRA ACLR 1+2
l EUTRA ACLR
l EUTRA measured with rectangular filter,
WCDMA measured with RRC filter
E-UTRAACLR1 UTRA ACLR2 UTRAACLR1
RB
E-UTRA channel
Channel
ΔfOOB
The purpose of this test is to verify that the UE transmitter does not cause unacceptable
interference to adjacent channels.
This is accomplished by determining the adjacent channel leakage [power] ratio (ACLR).
November 2012 | LTE measurements| 126
Adjacent Channel Leakage Ratio, ACLR
2 adjacent WCDMA
carriers, 5MHz BW
1 adjacent LTE
carrier, 20MHz BW
Active LTE
carrier, 20MHz BW
November 2012 | LTE measurements| 127
Occupied Bandwidth - OBW
99% of mean power
Occupied bandwidth is defined
as the bandwidth containing 99 %
of the total integrated mean power
of the transmitted spectrum
Transmission
Bandwidth [RB]
Transmission Bandwidth Configuration [RB]
Channel Bandwidth [MHz]
Res
ou
rce
blo
ck
Ch
an
nel e
dg
e
Ch
an
nel e
dg
e
DC carrier (downlink only)Active Resource Blocks
November 2012 | LTE measurements| 128
Spectrum Emission Mask, SEM
99% of mean power
OBW: Occupied bandwidth, defined as 99% of mean power
1 MHz RBW
SEM: Spectrum ‚Emission Mask, measured with different resolution bandwidth,
1 MHz or 30 kHz RBW
30 kHz RBW
November 2012 | LTE measurements| 129
Impact on SEM limit definition
Spectrum emission limit (dBm)/ Channel bandwidth
ΔfOOB
(MHz)
1.4
MH
z
3.0
M
Hz
5
M
Hz
10
M
Hz
15
M
Hz
20
M
Hz
Measurement
bandwidth
0-1 -10 -13 -15 -18 -20 -21 30 kHz
1-2.5 -10 -10 -10 -10 -10 -10 1 MHz
2.5-5 -25 -10 -10 -10 -10 -10 1 MHz
5-6 -25 -13 -13 -13 -13 1 MHz
6-10 -25 -13 -13 -13 1 MHz
10-15 -25 -13 -13 1 MHz
15-20 -25 -13 1 MHz
20-25 -25 1 MHz
Limits depend
on channel
bandwidth
Limits vary
dependent on offset
from assigned BW
November 2012 | LTE measurements| 130
SEM definition depends on band
Spectrum emission limit (dBm)/ Channel bandwidth
ΔfOOB
(MHz)
1.4
MHz
3.0
MHz
5
MHz
10
MHz
Measurement
bandwidth
0-0.1 -13 -13 -15 -18 30 kHz
0.1-1 -13 -13 -13 -13 100 kHz
1-2.5 -13 -13 -13 -13 1 MHz
2.5-5 -25 -13 -13 -13 1 MHz
5-6 -25 -13 -13 1 MHz
6-10 -25 -13 1 MHz
10-15 -25 1 MHz
Spectrum emission mask depends on additionally signalled band values NS_0x
e.g.
NS_07
=band 13
November 2012 | LTE measurements| 131
Transmitter Spurious Emissions
Spurious domain
RB
Channel bandwidth Spurious domain
ΔfOOB
ΔfOOB
E-UTRA Band
Frequency Range Maximum
Level
Measurement
Bandwidth
9 kHz f < 150 kHz -36 dBm 1 kHz
150 kHz f < 30 MHz -36 dBm 10 kHz
30 MHz f < 1000 MHz -36 dBm 100 kHz
1 GHz f < 12.75 GHz -30 dBm 1 MHz
The spurious emission limits apply for the frequency
ranges that are more than ΔfOOB (MHz) from the
edge of the channel bandwidth
Channel
bandwidth
1.4
MHz
3.0
MHz
5
MHz
10
MHz
15
MHz
20
MHz
ΔfOOB (MHz) 2.8 6 10 15 20 25
…to verify that UE transmitter does not cause unacceptable interference
to other channels or other systems in terms of transmitter spurious emissions.
November 2012 | LTE measurements| 132
LTE Uplink: PUCCH
frequency
Allocation of
PUCCH only.
November 2012 | LTE measurements| 133
PUCCH measurements
PUCCH is transmitted on the 2 side
parts of the channel bandwidth
November 2012 | LTE measurements| 134
Transmit intermodulation
The transmit intermodulation performance is a measure of the capability of the transmitter
to inhibit the generation of signals in its non linear elements caused by presence of the
wanted signal and an interfering signal reaching the transmitter via the antenna.
User Equipment(s) transmitting in close vicinity of each other can produce intermodulation products,
which can fall into the UE, or eNode B receive band as an unwanted interfering signal.
The UE intermodulation attenuation is defined by the ratio of the mean power of the wanted signal
to the mean power of the intermodulation product when an interfering CW signal is added at a level
below the wanted signal at each of the transmitter antenna port with the other antenna port(s)
if any is terminated.
BWChannel (UL) 5MHz 10MHz 15MHz 20MHz
Interference Signal
Frequency Offset 5MHz 10MHz 10MHz 20MHz 15MHz 30MHz 20MHz 40MHz
Interference CW Signal
Level -40dBc
Intermodulation Product -29dBc -35dBc -29dBc -35dBc -29dBc -35dBc -29dBc -35dBc
Measurement bandwidth 4.5MHz 4.5MHz 9.0MHz 9.0MHz 13.5MHz 13.5MHz 18MHz 18MHz
November 2012 | LTE measurements| 135
Spurious Emissions
Frequency Band Measurement
Bandwidth
Maximum
level
30MHz f < 1GHz 100 kHz -57 dBm
1GHz f 12.75 GHz 1 MHz -47 dBm
General receiver spurious emission requirements
The spurious emissions power is the power of emissions generated or
amplified in a receiver that appear at the UE antenna connector.
November 2012 | LTE measurements| 136
SEM – effect of scrambling
Modulation
mapper
Transform
precoderScrambling
SC-FDMA
signal gen.
Resource
element mapper
Constant
Bit pattern
Scrambling
should
randomize the
bit stream
Scrambling
disabled +
constant bit
stream
November 2012 | LTE measurements| 137
LTE Receiver Measurements
1 Reference sensitivity level
2 Maximum input level
3 Adjacent Channel Selectivity (ACS)
4 Blocking characteristics
4.1 In-band blocking
4.2 Out-of-band blocking
4.3 Narrow band blocking
5 Spurious response
6 Intermodulation characteristics
6.1 Wide band Intermodulation
7 Spurious emissions
November 2012 | LTE measurements| 138
LTE open loop power control and RSRP reporting
UE
UE measures RSRP:
Reference Signal
Receive Power
System Information:
referenceSignalPower
[-60 .. 50]dBm
PDSCH, PUCCH or
SRS transmit power
at UE
PDSCH, PUCCH or
SRS receive power
at eNodeB
Pathloss =
referenceSignalPower - RSRP
UE reports RSRP:
back to the eNB
November 2012 | LTE measurements| 139
Reference Signal Receive Power, RSRP
R
R
R
R
Entire bandwidth
Scan over entire bandwidth,
RSRP = power of 1 symbol, as mean power
November 2012 | LTE measurements| 140
Received Signal Strength Indicator, RSSI
R
R
Entire bandwidth R
R
interferer
noise
November 2012 | LTE measurements| 141
LTE measurements
RSRP = Reference Signal Received Power
Definition Reference signal received power, the mean measured power of the
reference symbols during the measurement period.
Applicable for TBD
E-UTRA Carrier RSSI
Definition E-UTRA Carrier Received Signal Strength Indicator, comprises the total
received wideband power observed by the UE from all sources, including co-
channel serving and non-serving cells, adjacent channel interference, thermal
noise etc.
Applicable for TBD
November 2012 | LTE measurements| 142
LTE measurements: RSRQ Reference Signal Received Quality
Definition Reference Signal Received Quality (RSRQ) is defined as the ratio N×RSRP/(E-
UTRA carrier RSSI), where N is the number of RB’s of the E-UTRA carrier
RSSI measurement bandwidth. The measurements in the numerator and
denominator shall be made over the same set of resource blocks.
E-UTRA Carrier Received Signal Strength Indicator (RSSI), comprises the
linear average of the total received power (in [W]) observed only in OFDM
symbols containing reference symbols for antenna port 0, in the
measurement bandwidth, over N number of resource blocks by the UE
from all sources, including co-channel serving and non-serving cells,
adjacent channel interference, thermal noise etc.
The reference point for the RSRQ shall be the antenna connector of the UE.
If receiver diversity is in use by the UE, the reported value shall not be lower
than the corresponding RSRQ of any of the individual diversity branches.
Applicable for RRC_CONNECTED intra-frequency,
RRC_CONNECTED inter-frequency
RSRQ = RSRP
RSSI
November 2012 | LTE measurements| 143
RX Measurements – general setup
Receive Sensitivity Tests
User
definable
DL
assignment
Table
(TTI based)
Specifies DL scheduling
parameters like
RB allocation
Modulation, etc.
for every TTI (1ms)
Transmit data
according to
table on PDSCH
ACK/NACK/DTX
Counting
Receive feedback
on PUSCH
or PUCCH
+
AWGN
Blockers
Adjacent channels
requirements in terms of throughput (BLER) instead of BER
Use both
Rx Antennas
November 2012 | LTE measurements| 144
Downlink channel power for Rx tests Physical Channel EPRE Ratio
PBCH PBCH_RA = 0 dB
PBCH_RB = 0 dB
PSS PSS_RA = 0 dB
SSS SSS_RA = 0 dB
PCFICH PCFICH_RB = 0 dB
PDCCH PDCCH_RA = 0 dB
PDCCH_RB = 0 dB
PDSCH PDSCH_RA = 0 dB
PDSCH_RB = 0 dB
PHICH PHICH_RB = 0 dB
Physical Channel EPRE Ratio
PBCH PBCH_RA = A
PBCH_RB = B
PSS PSS_RA = A
SSS SSS_RA = A
PCFICH PCFICH_RB =
B
PDCCH PDCCH_RA = A
PDCCH_RB = B
PDSCH PDSCH_RA = A
PDSCH_RB = B
PHICH PHICH_RB = B
For tests where no Ref. Signal
boosting is applied
For tests where Ref. Signal
boosting is applied, e.g. ρA = -3dB
November 2012 | LTE measurements| 145
Fixed reference channels
Parameter Unit Value
Channel bandwidth MHz 1.4 3 5 10 15 20
Allocated resource blocks 6 15 25 50 75 100
Subcarriers per resource block 12 12 12 12 12 12
Allocated subframes per Radio Frame 10 10 10 10 10 10
Modulation QPSK QPSK QPSK QPSK QPSK QPSK
Target Coding Rate 1/3 1/3 1/3 1/3 1/3 1/3
Number of HARQ Processes Processes 8 8 8 8 8 8
Maximum number of HARQ transmissions 1 1 1 1 1 1
Transport block CRC Bits 24 24 24 24 24 24
Number of Code Blocks per Sub-Frame
(Note 4)
For Sub-Frames 1,2,3,4,6,7,8,9 Bits 1368 3780 6300 13800 20700 27600
For Sub-Frame 5 Bits n/a n/a n/a n/a n/a n/a
For Sub-Frame 0 Bits 528 2940 5460 12960 19860 26760
Max. Throughput averaged over 1 frame kbps 341.6 1143.2 1952.8 3952.8 6040.8 7884
UE Category 1-5 1-5 1-5 1-5 1-5 1-5
Fixed reference channels defined in TS 36.101 for receiver quality measurements
November 2012 | LTE measurements| 146
RX sensitivity level
Channel bandwidth
E-UTRA
Ban
d
1.4 MHz
(dBm)
3 MHz
(dBm)
5 MHz
(dBm)
10 MHz
(dBm)
15 MHz
(dBm)
20 MHz
(dBm)
Duplex
Mode
1 - - -100 -97 -95.2 -94 FDD
2 -104.2 -100.2 -98 -95 -93.2 -92 FDD
3 -103.2 -99.2 -97 -94 -92.2 -91 FDD
4 -106.2 -102.2 -100 -97 -95.2 -94 FDD
5 -104.2 -100.2 -98 -95 FDD
6 - - -100 -97 FDD
Criterion: throughput shall be > 95% of possible maximum
(depend on RMC)
Sensitivity depends on band,
channel bandwidth and RMC
under test
Extract from TS 36.521
November 2012 | LTE measurements| 147
Block Error Ratio and Throughput
Rx
quality DL
signal
Channel
setup Criterion: throughput shall be
> 95% of possible maximum
(depending on RMC)
November 2012 | LTE measurements| 148
Details LTE FDD signaling Rx Measurements
l Rx Measurements
l Counting
– ACKnowledgement (ACK)
– NonACKnowledgement
(NACK)
– DTX (no answer from UE)
l Calculating
l BLER (NACK/ALL)
l Throughput [kbps]
November 2012 | LTE measurements| 149
Rx measurements: BLER definition
PDCCH, scheduling info
PDSCH, as PRBS
ACK/NACK feedback
Count
#NACKs
and
calculate
BLER
Assumption is that eNB
Power = UE Rx power
November 2012 | LTE measurements| 150
Rx measurements: BLER definition
PDCCH, scheduling info
PDSCH, user data
ACK/NACK feedback
•ACK = UE properly
Receives PDCCH + PDSCH
•NACK = UE properly receives
PDCCH but does not understand
PDSCH
•DTX = UE does not understand
PDCCH
ACK relative =
NACK relative =
DTX relativ =
DTXNACKACK
ACK
###
#
DTXNACKACK
NACK
###
#
DTXNACKACK
DTX
###
#
BLER = DTXNACKACK
DTXNACK
###
##
November 2012 | LTE measurements| 151
BLER verification
Downlink error
insertion to verify
the UE reports
November 2012 | LTE measurements| 152
Transportation Block Size Index
Transportation block size
FEC User data
Flexible ratio between data and FEC = adaptive coding
TBS Idx
0
9
15
26
Modulation
QPSK
16-QAM
64-QAM
S/N
Data
rate
No change in data
rate, but in reliability
November 2012 | LTE measurements| 153
Throughput versus SNR
November 2012 | LTE measurements| 154
UE sensitivity – maximum input level
Rx Parameter Units Channel bandwidth
1.4 MHz 3 MHz 5 MHz 10 MHz 15 MHz 20 MHz
Wanted signal mean power dBm -25
Maximum input level
November 2012 | LTE measurements| 155
UE sensitivity – RF sensitivity measurement
minimum input level
Channel bandwidth
E-UTRA
Ban
d
1.4 MHz
(dBm)
3 MHz
(dBm)
5 MHz
(dBm)
10 MHz
(dBm)
15 MHz
(dBm)
20 MHz
(dBm)
Duplex
Mode
1 - - -100 -97 -95.2 -94 FDD
2 -104.2 -100.2 -98 -95 -93.2 -92 FDD
3 -103.2 -99.2 -97 -94 -92.2 -91 FDD
4 -106.2 -102.2 -100 -97 -95.2 -94 FDD
5 -104.2 -100.2 -98 -95 FDD
6 - - -100 -97 FDD
PRBS
ACK/NACK
November 2012 | LTE measurements| 156
Adjacent Channel Selectivity (ACS)
Requirement per BW, LTE interferer
AC
S=
33
dB
[1.4MHz]
1.4MHz LTE 1.4MHz LTE
Pown = - 88.5
Padj = - 57.5
1.4MHz
2dB IM Nt = - 90.5
AC
S=
33
dB
[1.4MHz]
1.4MHz LTE 1.4MHz LTE
Pown = - 88.5
- 57.5
1.4MHz
2dB IM 2dB IM Nt = - 90.5
[3MHz]
AC
S=
33
dB
3MHz LTE 3MHz LTE
Pown = - 84.5
Nt = - 86.5
Padj = - 53.5
3MHz
2dB IM
[3MHz]
AC
S=
33
dB
3MHz LTE 3MHz LTE
Pown = - 84.5
Nt = - 86.5
= - 53.5
3MHz
2dB IM 2dB IM
AC
S=
33
dB
5MHz
5MHz LTE 5MHz LTE
Pown = - 82.3
Nt = - 84.3
Padj = - 51.3
5MHz
2dB IM
AC
S=
33
dB
5MHz
5MHz LTE 5MHz LTE
Pown = - 82.3
Nt = - 84.3
= - 51.3
5MHz
2dB IM 2dB IM
AC
S=
33
dB
10MHz
5MHz LTE 10MHz LTE
Pown = - 79.3
Nt = - 81.3
Padj = - 48.3
7.5MHz
2dB IM
AC
S=
33
dB
10MHz
5MHz LTE 10MHz LTE
Pown = - 79.3
Nt = - 81.3
= - 48.3
7.5MHz
2dB IM 2dB IM
Pown = - 77.5
Nt = - 79.5
Padj = - 49.5
AC
S=
3
0d
B
15MHz
5MHz LTE 15MHz LTE
10MHz
2dB IM Pown = - 77.5
Nt = - 79.5
= - 49.5
AC
S=
3
0d
B
15MHz
5MHz LTE 15MHz LTE
10MHz
2dB IM 2dB IM
Pown= -76.3
Nt= -78.3
Padj,wcdma= -51.3
ACS=
27
dB
20MHz
5MHz LTE20MHz LTE
12.5MHz
2dB IMPown= -76.3
Nt= -78.3
Padj,wcdma= -51.3
ACS=
27
dB
20MHz
5MHz LTE20MHz LTE
12.5MHz
2dB IM2dB IM
… is a measure of a receiver's ability to receive a E-UTRA signal at its assigned channel frequency
in the presence of an adjacent channel signal at a given frequency offset from the centre frequency of
the assigned channel and with the given power
November 2012 | LTE measurements| 157
Adjacent Channel selectivity
Channel bandwidth
Rx Parameter Units 1.4 MHz 3 MHz 5 MHz 10 MHz 15 MHz 20 MHz
ACS dB 33.0 33.0 33.0 33.0 30 27
Rx Parameter Units Channel bandwidth
1.4 MHz 3 MHz 5 MHz 10 MHz 15 MHz 20 MHz
Wanted signal
mean
power
dBm
REFSENS + 14 dB
PInterferer
dBm REFSENS
+45.5d
B
REFSENS
+45.5
dB
REFSENS
+45.5dB*
REFSENS
+45.5d
B
REFSENS
+42.5d
B
REFSENS
+39.5dB
BWInterferer MHz 1.4 3 5 5 5 5
FInterferer (offset) MHz 1.4+0.0025 /
-1.4-0.0025
3+0.0075
/
-3-0.0075
5+0.0025
/
-5-0.0025
7.5+0.0075
/
-7.5-0.0075
10+0.0125
/
-10-0.0125
12.5+0.0025
/
-12.5-0.0025
Adjacent Channel Selectivity (ACS) is a measure of a receiver's ability to receive a E-UTRA
signal at its assigned channel frequency in the presence of an adjacent channel signal at a given
frequency offset from the centre frequency of the assigned channel and with the given power
November 2012 | LTE measurements| 158
Receiver performance - Blocking tests
frequency
f >> system bandwidth
fc fB
In-band blocking
Out-of-band blocking
Narrow band blocking
Throughput
shall be ≥
95%
CW interferer at a frequency,
which is less than the nominal channel spacing
5MHz LTE interferer
15MHz below to 15MHz above the UE receive band
CW interferer , more than 15MHz below to
15MHz above the UE receive band
November 2012 | LTE measurements| 159
Spurious Response Spurious response verifies the receiver's ability to receive a wanted signal on its assigned
channel frequency without exceeding a given degradation due to the presence of an unwanted
CW interfering signal at any other frequency at which a response is obtained i.e. for which
the out of band blocking limit as specified in sub-clause 7.6.2 is not met.
6/6,24max RBN
RBN
8/)2(,8max CRBsRB LN
RBN
CRBsL
For Table 7.6.2.3-2 in frequency range 1, 2 and 3, up to
exceptions are allowed for spurious response frequencies in each assigned frequency channel when measured using a 1MHz step size, where
is the number of resource blocks in the downlink transmission bandwidth configuration (see Figure 5.4.2-1).
For these exceptions the requirements of clause 7.7 Spurious Response are applicable. For Table 7.6.2.3-2 in frequency range 4, up to
exceptions are allowed for spurious response frequencies in each assigned frequency channel when measured using a 1MHz step size, where
is the number of resource blocks in the downlink transmission bandwidth configurations (see Figure 5.4.2-1) and
is the number of resource blocks allocated in the uplink. For these exceptions the requirements of clause 7.7 Spurious Response are applicable.
Out of band blocking
E-UTRA
band
Parameter Units Frequency
range 1 range 2 range 3 range 4
PInterferer dBm -44 -30 -15 -15
1, 2, 3, 4, 5,
6, 7, 8, 9, 10,
11, 12, 13,
17, 18, 19,
20, 21,
33,34,35,36,3
7,38,39,40
FInterferer
(CW) MHz
FDL_low -15 to
FDL_low -60
FDL_low -60 to
FDL_low -85
FDL_low -85 to
1 MHz -
FDL_high +15 to
FDL_high + 60
FDL_high +60 to
FDL_high +85
FDL_high +85 to
+12750 MHz -
2, 5, 12, 17 FInterferer MHz - - - FUL_low - FUL_high
NOTE: For the UE which supports both Band 11 and Band 21 the out of blocking is FFS.
November 2012 | LTE measurements| 160
Rx quality - Intermodulation
frequency
Wanted Signal C
Modulated
Interferer Imod
f
Unmodulated
Interferer Icw
f
fc fcw fmod
Throughput
shall be ≥
95%
See TS 36.101 for power and frequency offset definitions
November 2012 | LTE measurements| 161
CQI reporting
SIR
high
low
high low
≡CQIn
≡CQIn-1
≡CQIn-2
≡CQIn+2
≡CQIn+1
Prevailing conditions of SIR
Optimum throughput
if the UE reports
CQIn
SIR changes, CQI reporting must follow!
Underrated
CQI report
Overrated
CQI report
Th
rou
gh
pu
t
November 2012 | LTE measurements| 162
CQI reporting
Calculate Median CQI,
Evaluate if more than 90% of reported CQI
Are in range of median CQI ±1
Network sends median CQI – evaluate BLER on median CQI
BLER on median CQI <= 10%
Network sends CQI +1
-> BLER must be
> 10%
BLER on median CQI > 10%
Network sends CQI -1
-> BLER must be
< 10%
November 2012 | LTE measurements| 163
Rx tests – test mode UE SS
ACTIVATE TEST MODE
ACTIVATE TEST MODE COMPLETE
UE SS
CLOSE UE TEST LOOP
CLOSE UE TEST LOOP COMPLETE
Test modes defined to perform
Rx measurements, loop back
possible in test mode
November 2012 | LTE measurements| 164
UTRAN stack: 2 loop back mode defined
PHYSICAL LAYER
Medium Access Control
MAC
Packet Data Convergence
Protocol PDCP
Radio Link Control
RLC
Loop back above
PDCP, i.e. Layer 2
November 2012 | LTE measurements| 165
Test loop mode A
Uplink
and downlink
may have
various
capacity
UE Test Loop Mode A Function
u 0 ,u 1 .......u K .................u N - 1
User data
Down link
User data
Uplink
u 0 ,u 1 .......u K - 1 u 0 ,u 1 .......u K - 1
UE Test Loop Mode A Function
User data
Down link
User data
Uplink
u 0 .. u K - 1 ..u N - 1 u 0 ..u K - 1 u 0 ...u N - 1 u 0 ...u N - 1
November 2012 | LTE measurements| 166
Test loop mode B
Packet Data Convergence
Protocol PDCP
Loop back above
PDCP, i.e. Layer 2
buffer
ΔΤ
PDU size
must match
Delayed loop back
November 2012 | LTE measurements| 167
Throughput measurements
Max throughput
possible in SISO
November 2012 | LTE measurements| 168
Rx measurements - throughput
Throughput
Measurement,
Settings for max
throughput
for SISO:
Number of
Resource blocks
Modulation scheme
Transport block size
November 2012 | LTE measurements| 169
LTE Downlink BLER and throughput
Rx quality,
Indicating NACKs when
Lowering the RS EPRE
Of the serving cell.
November 2012 | LTE measurements| 170
Throughput + CQI in LTE
Change of
RF
condition-
> lower
data rate
UE sends
different
CQI
values
November 2012 | LTE measurements| 171
MIMO testing For MIMO, enable cell
One antenna Two antennas Four antennas
eNode B Correlation 1eNBR
1
1eNBR
1
1
1
1
*9
1*9
4*
91*
91*
94
94
91*
91
94
91
eNBR
MIMO correlation
Models from
TS 36.521
November 2012 | LTE measurements| 172
MIMO in LTE: BLER and throughput
November 2012 | LTE measurements| 173
Throughput measurements
MIMO active,
2 streams with
different data rate
November 2012 | LTE measurements| 174
Why do we need fading?
l 3GPP specifies various tests under conditions of fading
l WCDMA performance tests
l HSDPA performance tests
l LTE performance tests
l LTE reporting of channel state information tests
See CMW capability lists for details
l Evaluation of MIMO performance gain requires fading
l Correlated transmission paths in MIMO connection
l Simulation of “real life conditions” in the lab
l Comparison of processing gain for different transmission modes
November 2012 | LTE measurements| 175
Most popular MIMO scheme to increase data rates: Spatial Multiplexing
TX
Ant 1
TX
Ant 2
Time
RX
Ant 1
h11
h21
n1
r1
MIMO
RX(e.g. ZF,
MMSE,MLD)
de2
de1
Sp
ace
d1
d2
Matix B
LO
n2
r2
h12
h22
RX
Ant 2
2 X 2
MIMO
Doubles max. data rates, however, at the expense of SNR @ receiver.
Thus, according to Shannon‘s law, decrease of performance.
Makes sense for low order modulation schemes only (QPSK, 16QAM),
or in case of very good SNR conditions, e.g. for receivers close to base stations.
No increase of total transmit power, i.e. distribution of transmit power across multiple transmit antennas!
November 2012 | LTE measurements| 176
How do we test under conditions of fading?
System
simulator
Channel emulator
RF
Fading Profile
November 2012 | LTE measurements| 177
How do we test under conditions of fading?
System
simulator
Channel emulator
IQ
Out
IQ
Out
IQ
In
IQ
In
RF
Fading Profile
I/Q Interface
Option
CMW-B510x
November 2012 | LTE measurements| 178
Internal fading in LTE
November 2012 | LTE measurements| 179
BLER results with and without fading
November 2012 | LTE measurements| 180
Automatic testing: KT100 LTE + internal fading
November 2012 | LTE measurements| 181
Measurement sample (open loop SM)
November 2012 | LTE measurements| 182
BLER vs. SNR Transmit/Receive Diversity
AWGN only
MCS 7 and 10
Fading EPA 5 Hz Low
MCS 7 and 10
~2dB
~2dB
November 2012 | LTE measurements| 183
GUI – IP Settings
November 2012 | LTE measurements| 184
LTE E2E using DAU
November 2012 | LTE measurements| 185
LTE E2E using DAU
November 2012 | LTE measurements| 186
Throughput end to end
November 2012 | LTE measurements| 187
End to end testing – ping response, RTT
November 2012 | LTE measurements| 188
What is IMS? A high level summary
l The success of the internet, using the Internet Protocol (IP) for
providing voice, data and media has been the catalyst for the
convergence of industries, services, networks and business models,
l IP provides a platform for network convergence enabling a
service provider to offer seamless access to any services,
anytime, anywhere, and with any device,
l 3GPP has taken these developments into account
with specification of IMS,
l IMS stands for IP Multimedia Subsystem,
l IMS is a global access-independent and standard-based IP
connectivity and service control architecture that enables
various types of multimedia services to end-users using
common internet-based protocols,
l Defines an architecture for the convergence of audio,
video, data and fixed and mobile networks.
How to merge IP
and cellular world??
November 2012 | LTE measurements| 189
3 GPP System Architecture Evolution
S-GW P-GW
Evolved nodeB UE
external
Evolved Packet Core
RAN
IMS
PSTN
PDN MME
Signaling interfaces
Data transport interfaces
All interfaces are packet switched
Access PDN
directly or via IMS
IMS to control
access + data
transfer
November 2012 | LTE measurements| 190
IMS Architecture
November 2012 | LTE measurements| 192
IMS protocol structure
Layer 1/2 Layer 1/2 (other IP CAN)
Layer 3 control IP / IP sec
UDP / TCP / SCTP
SIP/SDP IKE RTP MSRP
Voice
video messaging
Control plane
user plane
Mobile com specific protocols IMS specific protocols
November 2012 | LTE measurements| 193
IMS protocol structure
Sonet, SDH, PDH, Ethernet, RF link = LTE
IPv4, IPv6
Megaco
Physical
layer
link
layer
network
layer
transport
layer
application
layer
Sonet, SDH, PDH, Ethernet, RF link = LTE
e.g. PPP, AAL2/ATM, AAL5/ATM, MAC
SIP
TCP UDP
RTSP RSVP RTCP RTP
H.323
Media
Encap.
e.g. H.261, MPEG
Media Transport
Quality of Service
Signaling
November 2012 | LTE measurements| 194
ISIM: IMS SIM
UICC
universal integrated circuit card
Security keys
Public user ID
Private user ID
Home network ID
PIN Administrative data
ISIM = application on UICC
USIM for LTE access
November 2012 | LTE measurements| 195
IMS LTE
IMS Registration and Authentication Comparison with LTE
ATTACH REQUEST REGISTER
AUTHENTICATION REQ
AUTHENTICATION RSP
ATTACH ACCEPT
401 UNAUTHORIZED
REGISTER
200 OK
November 2012 | LTE measurements| 196
SIP registration request Calculate RES, REG request
401 User not authorized 200 OK
What is IMS? Registration with IMS
l Prior to IMS registration the UE must discover an IMS entry point
(i.e. P-CSCF), which is done through an activation of a PDP context
for SIP signaling over 2G (GPRS) or 3G (WCDMA, C2K, EV-DO).
l First, there was SIM (Subscriber Identity
Module)…than there was USIM (Universal
SIM)…and now there is ISIM (IP Multimedia
Service Module),
– Public User Identity (identify a user),
– Private User Identity (users subscription),
HSS
I-CSCF
S-CSCF
P-CSCF
Retrieve S-CSCF
capabilities
Retrieve
user profile
November 2012 | LTE measurements| 197
IMS: SMS over IMS Message flow for a mobile originated SMS
RP-DATA ( SMS-SUBMIT)
RP-ACK ( SMS-SUBMIT REPORT)
RP-ACK
RP-DATA ( SMS-STATUS REPORT)
SMS Delivery
SIP MESSAGE
SIP MESSAGE
SIP MESSAGE
SIP MESSAGE
SIP 200 OK
SIP 200 OK
SIP 200 OK
SIP 200 OK
November 2012 | LTE measurements| 198
SMS over IMS
I-CSCF
S-CSCF
P-CSCF
HSS
IP based Core
Access Network,
i.e. EPC
IP-SM-GW
SMS-SC
IP short message
Gateway to connect
S-CSCF to SMS
serving centre
November 2012 | LTE measurements| 199
LTE Positioning with SUPL 2.0
UE E-SMLC
LPP over SUPL
User plane solution
LPP over RRC
Control plane solution
SET SLP
Target
Device LPP
Location
Server Assistance data
Measurements based on reference sources*
eNB
LTE radio
signal
SUPL enabled
Terminal
SUPL location
platform
Enhanced Serving
Mobile Location Center
November 2012 | LTE measurements| 200
l LTE has been designed as a fully packet-orientated, “all-IP”-
based, multi-service system with a flat network architecture,
l Technical challenges offering circuit-switched services (Voice, SMS)
via LTE
l 3GPP has defined IMS as long-term solution providing
circuit-switched services, for the short- / mid-term there is
no industry-wide consensus, but different approaches,
l Short-/mid-term: Circuit-switched fallback (CS fallback),
– SMS. “SMS over SG”, means SMS via Non-Access Stratum (NAS)
signaling,
– Voice. Fallback to 3G or 2G technology to take the call,
l VOLGA – Voice over LTE Generic Access – Call setup time increases while using CS fallback,
l OneVoice Initiative formed to push for Voice over LTE (VoLTE)
based on IMS.
Background for IMS and relation to LTE?
November 2012 | LTE measurements| 201
How to connect E-UTRAN to CS services?
l Connection via IMS: 3GPP and OneVoice initiative
l Voice over LTE Generic Access – VoLGA Forum – interim solution
l CS Fallback CSFB for voice calls to 2G or 3G services – preferred interim solution
l Evolved MSC, eMSC – CS Services via EPS – network operator proposal, interim solution
l SRVCC – Single Radio Voice Call Continuity
l SV-LTE – simultaneous voice and LTE
l OTT, Over the top – propietary solution, application based
First a big mess,
Now it seems to be OneVoice
November 2012 | LTE measurements| 202
IMS: Voice over IMS Message flow for a mobile originated call
Resource Reservation
INVITE (SDP offer)
PRACK
UPDATE (SDP)
180 RINGING
183 Session Progress (SDP offer)
200 OK (PRACK)
200 OK (UPDATE) (SDP)
PRACK
200 OK (PRACK)
Resource Reservation
200 OK (INVITE)
ACK
November 2012 | LTE measurements| 203
Voice over IMS: IMS call establishment
P-CSCF S-CSCF
1. Invite (Initial SDP Offer)
2. Invite (Initial SDP Offer)
5. Offer Response
9. Response Conf (Opt SDP)
13. Conf Ack (Opt SDP)
11. Response Conf (Opt SDP)
14. Conf Ack (Opt SDP)
19. Reservation Conf
17. Reservation Conf
20. Reservation Conf
16. Reservation Conf
22. Ringing
Originating Home Network
4. Invite (Initial SDP Offer)
6. Offer Response
8. Offer Response
12. Response Conf (Opt SDP)
15. Conf Ack (Opt SDP)
18. Reservation Conf
21. Reservation Conf
26. 200 OK
31. ACK 32. ACK
27. 200 OK
29. 200 OK
23. Ringing 24. Ringing
33. ACK
3. Service Control
UE
7. Authorize QoS Resources
10. Resource Reservation
25. Alert User 28. Enabling of
Media Flows
30. Start Media
Terminating Network
November 2012 | LTE measurements| 204
Voice over IMS: IMS protocol profile Codec mode Source codec bit-rate
AMR_12.20 12,20 kbit/s (GSM EFR)
AMR_10.20 10,20 kbit/s
AMR_7.95 7,95 kbit/s
AMR_7.40 7,40 kbit/s (IS-641)
AMR_6.70 6,70 kbit/s (PDC-EFR)
AMR_5.90 5,90 kbit/s
AMR_5.15 5,15 kbit/s
AMR_4.75 4,75 kbit/s
AMR_SID 1,80 kbit/s (see note 1)
Adaptive Multirate
Codecs are used
In VoIP over IMS
November 2012 | LTE measurements| 205
QoS class identifiers QCI
QCI Resource
Type
Priority Packet Delay
Budget
Packet Error
Loss
Rate
Example Services
1
GBR
2 100 ms 10-2 Conversational Voice
2 4 150 ms 10-3 Conversational Video (Live Streaming)
3 3 50 ms 10-3 Real Time Gaming
4 5 300 ms 10-6 Non-Conversational Video (Buffered Streaming)
5
Non-GBR
1 100 ms 10-6 IMS Signalling
6 6 300 ms
10-6
Video (Buffered Streaming)
TCP-based (e.g. www, e-mail, chat, ftp, p2p
file sharing, progressive video, etc.)
7 7 100 ms
10-3
Voice, Video (Live Streaming),
Interactive Gaming
8 8
300 ms
10-6
Video (Buffered Streaming)
TCP-based (e.g. www, e-mail, chat, ftp, p2p
file sharing, progressive video, etc.) 9 9
November 2012 | LTE measurements| 206
Voice over LTE – protocol profiles
PHYSICAL LAYER
Medium Access Control
MAC
Radio Link Control
RLC
Packet Data Convergence
PDCP
UDP/ TCP
IP
AMR codec
Use robust header compression or IP
Short PDCP header is used
Use RLC in UM mode
Small sequence number is used
SRB1 and 2 are supported for
DCCH + one UM DRB with QCI 1 for voice
for SIP signaling + one AM DRB QCI 5 for
SIP signaling + one AM DRB QCI 8 for
IMS traffic
TTI bundling + DRX to reduce PDCCH
Signaling + Semi-persistend scheduling
Optimize transmission of
Voice by configuring
Lower layers
November 2012 | LTE measurements| 207
IMS: Voice over IMS Interaction with EPS
l Resource reservation (QoS) can
be achieved with separate Radio
Bearers
QCI Quality of Service Class Indicator
GBR Guaranteed Bitrate
DRB Data Radio Bearer
PHY
MAC
RLC
PDCP
Default
Bearer
Dedicated
Bearer
SIP
signalling QCI = 5
Non-
GBR AM DRB
Voice QCI = 1 GBR UM DRB
November 2012 | LTE measurements| 208
VoLTE connection to CS via IMS
I-CSCF
S-CSCF
P-CSCF
HSS
MGCF BGCF
MG
PSTN
CS
network
IP based Core
Access Network,
i.e. EPC
BGW
User plane
Control plane
CS Connection via Boarder and Media Gateway of IMS
How to connect VoLTE
To legacy network?
November 2012 | LTE measurements| 209
IMS connection to CS services - arguments
l IMS can provide real end-to-end connection
l IMS defines end-to-end quality of service profiles
l IMS is completely based on Internet Protocol
l Supplementary services can be realized
l Several application servers needed
l Not widely implemented yet – many operators are reluctant
l IMS software client needed on UE side
l What happens under heavy load condition?
November 2012 | LTE measurements| 210
Radio Access Technologies today
GERAN
UTRAN
CDMA2K
1xEVDO
EUTRAN
LTE coverage is not fully up from day one
-> interworking with legacy networks is essential!!!
November 2012 | LTE measurements| 211
Voice calls in LTE
l There is one common solution: Voice over IMS l -> also named Voice over LTE VoLTE or OneVoice initiative
But….
What if IMS is not available at first rollout?
-> interim solution called Circuit Switched Fallback CSFB = handover to
2G/3G
-> or Simultaneous Voice on 1XRTT and LTE, SV-LTE = dual receiver
What is if LTE has no full coverage?
-> interworking with existing technologies, Single Radio Voice Call Continuity,
SRVCC
November 2012 | LTE measurements| 212
2G or 3G CS fallback
E-UTRAN MME IMS
Voice call
Voice over IMS is the solution,
but IMS is maybe not available in the first network roll-out.
Need for transition solution:
Circuit Switched Fall Back, CSFB move the call to 2G or 3G
November 2012 | LTE measurements| 213
2G or 3G CS fallback
UE
E-UTRAN MME
SGSN
MSC UTRAN
GERAN
Only for signalling
Only packet switched connections
Voice calls are
routed via 2G or 3G
CS
connection
as fallback
to legacy
networks
November 2012 | LTE measurements| 214
CSFB issues and questions
UE E - UTRAN MME LTE Uu S 1 - MME
GERAN
UTRAN
Um
Uu
SGSN
MSC Server
SGs
Gs
A
Iu - cs
Gb
Iu - ps
S 3
•Is it a handover command or a command to redirect to a new RAN ? i.e.
the UE selects the target cell or the EUTRAN commands the target cell
•Is there any information about the target RAN available (SysInfo)?
•Is there a packet data connection PDN active or not?
•Will the PDN be suspended or continued in the target RAN?
•Will the UE re-initiate the PDN or continue?
Handover or
Redirection?
Target cell
assigned or
selected by UE?
November 2012 | LTE measurements| 215
CS fallback options to UTRAN and GERAN
Feature
group
index, UE
indicates
CSFB
support
November 2012 | LTE measurements| 216
CS fallback to 1xRTT
E-UTRAN
MME
Serving/PDN GW
SGi
1xRTT CS Access
1xRTT MSC
1xCS IWS
S102
S11 S1-MME
S1-U
A1
A1
Tunnelled 1xRTT messages
1xCS CSFB
UE
1xCS CSFB
UE
S102 is the
reference point
between MME and
1xCS interworking
solution
Tunneling of
messages between
1xRTT MSC and UE
November 2012 | LTE measurements| 217
CS fallback to 1xRTT
November 2012 | LTE measurements| 218
CS fallback - arguments
l E-UTRAN and GERAN/UTRAN coverage must overlap
l No E-UTRAN usage for voice
l No changes on EPS network required
l Gs interface MSC-SGSN not widely implemented
l Increased call setup time
l No simultaneous voice + data if 2G network/UE does not support DTM
l SMS can be used without CS fallback, via E-UTRAN
November 2012 | LTE measurements| 219
l Call setup delay
l Call drop due to handover
l Blind hand-over is used for CSFB
l Data applications are interupted
l Legacy RAN coverage needed
Why not CSFB?
November 2012 | LTE measurements| 220
Dual receiver 1xCSFB
UE
eNB for LTE
CDMA2000 cell
Circuit switched
1xRTT registration
Packet switched
EUTRAN registration
Dual receiver 1xCSFB UEs can handle separate mobility and
registration procedures 2 radio links at the same
time. UE is registered to 2 networks, no coordination required.
When CS connection in 1xRTT,
dual receiver UE leaves EUTRAN!
November 2012 | LTE measurements| 221
SV-LTE: Simultaneous CDMA200 + LTE
UE
eNB for LTE
CDMA2000 cell
Circuit switched
1xRTT connection
Packet switched
EUTRAN connection
Simultaneous Voice UEs can handle 2 radio links at the same
time. UE is registered to MME and CDMA2K independently
November 2012 | LTE measurements| 222
OTT – over the top
S-GW P-GW
Evolved nodeB UE
Evolved Packet Core
EUTRAN
PDN
Application
Voice call as application, e.g. Skype, Google talk, …
November 2012 | LTE measurements| 223
OTT – over the top - arguments
S-GW P-GW
Evolved nodeB UE
Evolved Packet Core
EUTRAN
PDN
Application
•Propietary solution, needs to be implemented in UE and AS
•Already implemented in computer networks – known application
•Support has to be accepted by operator
•No Inter-RAT handover is possible
November 2012 | LTE measurements| 224
SMS transfer in LTE
PHYSICAL LAYER
Medium Access Control
MAC
Radio Resource Control
RRC
Contr
ol &
Measure
ments
Radio Link Control
RLC
Packet Data Convergence
PDCP
EMM ESM User plane
Transport channels
Logical channels
Radio Bearer
Encapsulate SMS in NAS
Control message->
SMS over SG
Send SMS over IMS
Using IP protocol
SMS over IMS
November 2012 | LTE measurements| 225
CSFB circuit switched fallback – SMS transfer
SMS-SC
UE E - UTRAN MME LTE - Uu S 1 - MME
GERAN
UTRAN
Um
Uu
SGSN
MSC Server
SGs
Gs
A
Iu - cs
Gb
Iu - ps
S 3
SCTP
L2
L1
IP
L2
L1
IP
SCTP
SGs MME MSC Server
SGsAP SGsAP
SMS transfer between SMS-SC and
MME via new interface SGs.
New protocol SGs interface
application protocol
For 1xRTT it
is the S102
interface
November 2012 | LTE measurements| 226
CSFB circuit switched fallback – SMS transfer
SMS -
2. Message transfer
3. Send Routeing Info For Short Message
4. Forward Short Message 5. Paging
6. Paging 7. Paging
9b. Downlink NAS Transport
9c. Uplink NAS Transport
13. Delivery report 12. Delivery report
8. Service Request
MS/UE eNodeB MSC/VLR HLR/HSS SMS -
MME SMS-
GMSC SC
1. EPS/IMSI attach procedure
8a. Service Request
9d. Uplink Unitdata
10. Uplink NAS Transport 11. Uplink Unitdata
14. Downlink Unitdata 16. Release Request
15. Downlink NAS Transport
9a. Downlink Unitdata
Mobile terminated SMS in idle mode, SMS over SG
SGs interface
No real fallback,
because SMS
is sent over
NAS signaling
November 2012 | LTE measurements| 227
CSFB circuit switched fallback – SMS transfer
l SMS can be transferred in the signaling messages
-> so no real circuit switched fallback
l CSFB ready at LTE launch? CSFB needs SGs
interface between MME and MSC
l Roaming: no guarantee that CSFB is supported
worldwide
l Specification issues: Not clear what happens if
SMS transfer occurs at ongoing CSFB procedure
l Test scenarios: No CSFB SMS test scenarios
defined yet
November 2012 | LTE measurements| 228
Single Radio Voice Call Continuity
Problem: in first network roll-out,
there is no full LTE coverage. How to
keep call active?
=> SRVCC
November 2012 | LTE measurements| 229
SRVCC – Single Radio Voice Call Continuity
UE
E-UTRAN MME
SGSN
MSC UTRAN
GERAN
User plane after handover
Handover of voice call
to 2G or 3G
IMS
User plane before handover
SRVCC is handover from
EUTRAN to 2G/3G if no
LTE coverage
November 2012 | LTE measurements| 230
Single Radio Voice Call Continuity
UE E-UTRAN MME MSC ServerTarget
UTRAN/GERAN
Measurement
Reports
Handover to UTRAN/GERAN
required
3GPP IMS
Initiates SRVCC for voice component
CS handover preparation
IMS Service Continuity Procedure
Handles PS-PS HO for
non-voice if needed
PS HO response to MME
(CS resources)
To eUTRAN
Coordinates SRVCC
and PS HO response Handover CMD
Handover
execution
November 2012 | LTE measurements| 231
Single Radio Voice Call Continuity
eNodeB = EUTRAN VoLTE call
time
VoIP in PS mode
Voice call in CS mode
NodeB = UTRAN
NodeB = UTRAN
Handover to UTRAN
Radio Bearer reconfiguration:
PS to CS mode
November 2012 | LTE measurements| 232
Handover requirements l Goal is to have seamless service continuity between LTE and other Legacy
Technologies (CDMA2000, WCDMA, GSM)
l Data and Voice services
l Support of all frequency bands and a single radio solution
l Transparent signaling to allow an independent protocol evolution for both
access systems
l Impact to QoS, e.g. service interruption, should be minimized
l RAT change procedure shall limit interruption time to less than 300ms
l 3GPP changes – Ability to tunnel signaling messages between E-UTRAN and 3GPP2
– Support measurements of 3GPP2 channels from E-UTRAN
– Capability to trigger a handover to a 3GPP2 system
l 3GPP2 changes – Minimal impact on today’s available cdma2000, Rev. 0 or Rev. A access terminal
– Minimal impact to legacy, deployed cdma2000 radio access networks
– Influence on circuit switched core network should be minimized
November 2012 | LTE measurements| 233
Handovers??
l What is :
l Intra-Frequency
– Changing between cells on same frequency -> different cell ID
l Inter-Frequency
– Changing between cells on differenct frequency
l Intra-Band
– Changing between cells inside the same band
l Inter-Band
– Changing between cells in different bands
l Inter-RAT
– Changing between cells using different RAT (LTE-WCDMA, LTE-GSM,
etc.)
November 2012 | LTE measurements| 234
Handover – what to discuss?
UE
eNodeB
EUTRAN cell
Redirection command?
UTRAN cell(s)?
Will the UE initiate the
change? -> re-selection
Will the network initiate
the change? ->
redirection or handover
Mandatory
for UE
supporting
CSFB
UE reads
SysInfo
Handover command?
GERAN cell(s)?
NW sends
SysInfo of
Target?
CDMA2K cell(s)?
November 2012 | LTE measurements| 235
Handover aspects – what to discuss?
l Some keywords that appear – and to be clarified in next
slides:
l Handover?
l Cell reselection?
l Cell change order?
l Redirection?
l Network assisted cell change, NACC?
l Circuit switched fallback, CS fallback?
November 2012 | LTE measurements| 236
Mobility aspects – support from UE
l There are some UE feature groups defined. The UE reports
this in the attach procedure to the network:
– A. Support of measurements and cell reselection procedure
in idle mode
– B. Support of RRC release with redirection procedure in
connected mode
– C. Support of Network Assisted Cell Change in connected
mode
– D. Support of measurements and reporting in connected
mode
– E. Support of handover procedure in connected mode
November 2012 | LTE measurements| 237
Mobility aspects – support from UE Feature GERAN UTRAN HRPD 1xRTT EUTRAN
A. Measurements and cell reselection
procedure in E-UTRA idle mode
Supported if
GERAN
band
support is
indicated
Supported if
UTRAN
band
support is
indicated
Supported if
CDMA200
0 HRPD
band
support is
indicated
Supported if
CDMA200
0 1xRTT
band
support is
indicated
Supported for
supported
bands
B. RRC release with blind redirection
procedure in E-UTRA connected
mode
Supported if
GERAN
band
support is
indicated
Supported if
UTRAN
band
support is
indicated
Supported if
CDMA200
0 HRPD
band
support is
indicated
Supported if
CDMA200
0 1xRTT
band
support is
indicated
Supported for
supported
bands
C. Cell Change Order (with or without)
Network Assisted Cell Change) in E-
UTRA connected mode
Group 10 N.A. N.A N.A N.A.
D. Inter-frequency/RAT measurements,
reporting and measurement reporting
event B2 (for inter-RAT) in E-UTRA
connected mode
Group 23 Group 22 Group 26 Group 24 Group 25
E. Inter-frequency/RAT handover procedure
in E-UTRA connected mode
Group 9
(GSM_conn
ected
handover)
Separate UE
capability bit
defined in
TS 36.306
for PS
handover
Group 8 (PS
handover)
or Group
27
(SRVCC
handover)
Group 12 Group 11 Group 13
Table from TS36.331
November 2012 | LTE measurements| 238
LTE Radio Resource Control States
Power-up
LTE_ACTIVE (RRC_CONNECTED) • IP address assigned,
• Connected to known cell.
OUT_OF_SYNCH • DL reception possible,
• No UL transmission.
IN_SYNCH • DL reception possible,
• UL transmission possible.
LTE random access procedure
[Initial Access; allocate C-RNTI, TA-ID, IP address]
LTE random access procedure
[to restore uplink synchronization]
LTE random access procedure
[Transition to LTE_ACTIVE state (IN_SYNCH)]
release of C-RNTI, allocate
DRX cycle for PCH
de-allocate Tracking Area ID (TA-ID) and IP address
LTE_DETACHED • No IP address assigned,
• UE location unknown.
LTE_IDLE (RRC_IDLE) • IP address assigned,
• UE position partially known.
User Equipment (UE) LTE/eHRPD-capable terminal
1. What about
mobility, when UE
is in IDLE state?
2. What about
mobility, when UE
is in CONNECTED state?
Cell search and selection
and system information
acquisition
© Rohde&Schwarz, 2010
November 2012 | LTE measurements| 239
Mobility between LTE and WCDMA/GSM Radio Access Aspects
Handover
CELL_PCH
URA_PCH
CELL_DCH
UTRA_Idle
E-UTRA
RRC_CONNECTED
E-UTRA
RRC_IDLE
GSM_Idle/GPRS
Packet_Idle
GPRS Packet
transfer mode
GSM_Connected
Handover
Reselection Reselection
Reselection
Connection
establishment/release
Connection
establishment/release
Connection
establishment/release
CCO,
Reselection
CCO with
optional
NACC
CELL_FACH
CCO, Reselection
November 2012 | LTE measurements| 240
IRAT Procedures Redirection
1. UE has an active RF session (EPS Bearer Context, PDP Context)
2. NW releases RRC connection and indicates target RAT and RF
channel in RRC Connection Release Message
3. UE indicates active PDP Contexts during Routing Area Update
procedure on target RAT
4. NW sets up radio bearer
5. For WCDMA → LTE redirection can also be signaled in RRC
Connection Request
6. Data connection is interrupted during the procedure
November 2012 | LTE measurements| 241
Redirection
AS-security has been activated, and SRB2 with at least one DRB are setup
RRCConnectionRelease
UE EUTRAN
November 2012 | LTE measurements| 242
Redirection to UMTS
UE
eNodeB
EUTRAN cell
RRC connection release message
with RedirectedCarrierInfo to
UTRAN
NodeB(s)
UTRAN cell(s)
UE will search for
suitable cell on
UARFCN and initiate
CS connection
RRC connection release with redirection without SysInfo
Mandatory
for UE
supporting
CSFB
UE reads
SysInfo
November 2012 | LTE measurements| 243
Redirection to UMTS
UE
eNodeB
EUTRAN cell
RRC connection release message
with RedirectedCarrierInfo to
UTRAN
NodeB
UTRAN cell
UE will go to indicated
cell and initiate CS
connection
RRC connection release with redirection with SysInfo
e-RedirectionUTRA
capability is set
by UE
Sys
Info
Rel. 9
feature UE reads
SysInfo
November 2012 | LTE measurements| 244
Redirection to GERAN
UE
eNodeB
EUTRAN cell
RRC connection release message
with RedirectedCarrierInfo to
GSM
BTS(s)
GSM cell(s)
UE will search for
suitable cell on ARFCN
and initiate CS
connection
RRC connection release with redirection without SysInfo
Mandatory
for UE
supporting
CSFB
November 2012 | LTE measurements| 245
Redirection to GERAN
UE
eNodeB
EUTRAN cell
RRC connection release message
with RedirectedCarrierInfo to
GSM
UE will go to indicated
cell and initiate CS
connection
RRC connection release with redirection with SysInfo
e-RedirectionUTRA
capability is set
by UE
Sys
Info
Rel. 9
feature
BTS(s)
GSM cell(s)
November 2012 | LTE measurements| 246
IRAT Procedures PS Handover
l UE has an active data session (EPS Bearer Context, PDP
Context)
l NW sends handover command e.g.
l LTE → WCDMA: MobilityFrom EUTRACommand
l WCDMA → LTE: HandoverFromUTRANCommand_EUTRA
l PS radio bearer is immediately setup on target RAT
November 2012 | LTE measurements| 247
Handover (Intra-LTE)
AS-security has been activated, and SRB2 with at least one DRB are setup
RRCConnectionReconfigurationComplete
RRCConnectionReconfiguration
UE EUTRAN
November 2012 | LTE measurements| 248
Packet Switched handover to other RAN
MobilityFromEUTRACommand ::= SEQUENCE {
rrc-TransactionIdentifier RRC-TransactionIdentifier,
criticalExtensions CHOICE {
c1 CHOICE{
mobilityFromEUTRACommand-r8 MobilityFromEUTRACommand-r8-IEs,
mobilityFromEUTRACommand-r9 MobilityFromEUTRACommand-r9-IEs,
spare2 NULL, spare1 NULL
},
criticalExtensionsFuture SEQUENCE {}
}
}
Contains this information element when
Falling back to legacy networks
MobilityFromEUTRACommand
UE EUTRAN
November 2012 | LTE measurements| 249
Handover (Intra-MME/Serving Gateway)
UE Source eNB
Measurement reporting
Handover decision
Handover request
Handover request Ack
RRC connection reconfiguration
Target eNB
MME
Admission Control
Detach from old,
sync to new cell
Deliver packets
to target eNB SN Status Transfer
Data forwarding Buffer packets
from source eNB
RRC connection reconfiguration complete
Path switch Req / Ack
UE context release
Flush buffer
Release resources
November 2012 | LTE measurements| 250
Handover to UMTS: Packet switched handover
UE
eNodeB
EUTRAN cell
MobilityFromEUTRACommand message
with purpose indicator = handover
to UTRAN
EUTRAN contains targetRATmessagecontainer,
= Inter-RAT info about target cell
NodeB(s)
UTRAN cell(s)
UE will select target cell
on UARFCN and
continue PS connection
Packet Switched handover to UTRAN
November 2012 | LTE measurements| 251
HandoverfromEUTRAN – target RAT message
targetRAT-Type Standard to apply targetRAT-MessageContainer
geran GSM TS 04.18, or 3GPP TS 44.018
3GPP TS 44.060
3GPP TS 44.060
HANDOVER COMMAND
PS HANDOVER COMMAND
DTM HANDOVER COMMAND
cdma2000-
1XRTT
C.S0001 or later, C.S0007 or later,
C.S0008 or later
cdma2000-
HRPD
C.S0024 or later
utra 3GPP TS 25.331 HANDOVER TO UTRAN
COMMAND
HandoverFromEUTRAN message contains control message
of target RAT. Possible messages are:
November 2012 | LTE measurements| 252
Mobility from EUTRAN – failure case
RRC connection re-establishment
MobilityFromEUTRACommand
UE EUTRAN
Radio link failure
in target RAT UE will try to
Reestablish
EUTRAN connection
November 2012 | LTE measurements| 253
UE mobility in LTE (RRC CONNECTED state) Measurement configuration, related RRC messages & information elements
RRCConnectionReconfiguration …
MeasConfig
... MeasConfig MeasObjectToAddModList
ReportConfigToAddMod
QuantityConfig
measGapConfig MeasObjectToAddModList …
MeasObjectCDMA2000
Neig Cell Info
Type of CDMA network (1xRTT, HRPD),
CDMA2000 carrier configuration, search
window size, cells to add/modify/remove
from the neighboring list, cell index (up to
32 cells), PN offset…
ReportConfigToAddMod …
ReportConfigInterRAT
Periodic or event (InterRAT: B1, B2) triggered
Reporting, hysteresis (0…15 dB), # of cells to
report excluding serving cell, report interval
(120, …, 10240ms, …, 60 min), time-to-trigger,
CDMA2000 threshold (0…63)
measGapConfig gp0 (0…39), gp1 (0…79)
Two gap pattern 0 and 1, gap length is 6 ms,
using two different Transmission Gap
Repetition Period of 40 or 80 ms
How? What?
When?
Each gap starts at SFN & subframe
meeting these conditions :
SFN mod T = FLOOR(gapOffset/10)
with T = MGRP/10
Subframe = gapOffset mod 10 When to retune the receiver to measure e.g. CDMA2000 or HRPD…
November 2012 | LTE measurements| 254
Inter-RAT Handover to GERAN: cell change order
UE
eNodeB
EUTRAN cell
MobilityFromEUTRACommand message
with purpose indicator = Cell Change Order
to GPRS
BTS(s)
GPRS cell(s)
UE will search for
suitable cell on ARFCN
and re-initiate PS
connection
Packet Switched cell change order to GPRS without NACC
(network assisted cell change)
Mandatory
for UE
supporting
CSFB
PS connection will be suspended
November 2012 | LTE measurements| 255
Inter-RAT Handover to GERAN: cell change order
UE
eNodeB
EUTRAN cell
MobilityFromEUTRACommand message
with purpose indicator = Cell Change Order
to GPRS
BTS
GPRS cell
UE will search for
suitable cell on ARFCN
and initiate PS
connection
Packet Switched cell change order to GPRS with NACC
(network assisted cell change)
Mandatory
for UE
supporting
CSFB
Sys
Info
PS connection will be suspended
November 2012 | LTE measurements| 256
Inter-RAT Handover to GERAN: handover
UE
eNodeB
EUTRAN cell
MobilityFromEUTRACommand message
with purpose indicator = handover
to GPRS
BTS
GPRS cell
UE will search for
suitable cell on ARFCN
and continue PS
connection
Packet Switched handover to GPRS
Mandatory
for UE
supporting
CSFB
PS connection will be handed over
November 2012 | LTE measurements| 257
LTE-RTT Handover
Circuit Switched Fallback, CSFB
Overview
November 2012 | LTE measurements| 258
3GPP Changes
l LTE Broadcast Channel
l CDMA System Time
l 1xEVDO, 1xRTT, WCDMA, GSM cell parameters
l Cell (re)selection parameters
l Broadcast as SIB Type 8 or via Dedicated RRC messages
l Tunneling
l Receiving 1xEVDO overhead messages with dual Rx ATs
l Measurement Gaps
November 2012 | LTE measurements| 259
Eg CDMA2000 Changes
l Air interface specification changes
l New protocols defined for
– Authentication: EAP-AKA
– IP Address Allocation : VSNCP
– Multiple PDN support : EMFPA
l Non-optimized and optimized handoff from LTE to eHRPD
l Preamble Initial Power for handover complete message
l Handover to 1xEV-DO Rev. B being considered
l Circuit-Switched Fallback (CS fallback) currently specified in
C.S0097-0
l Core network changes
l S101 interface – signaling interface
l S103 interface – bearer interface
l PDSN extension (now called HSGW)
November 2012 | LTE measurements| 260
Definitions cont’d
l Non-Optimized Handovers
l Without the use of tunneled signaling (S101)
l Optimized Handovers
l Less than 300ms interruption
l Uses tunneled signaling interface
l Two step process
– Pre registration / Session maintenance
– Handover preparation/handover execution
l Types of handovers
– Idle mode handover (cell re-selection)
– Active mode handover
November 2012 | LTE measurements| 261
CS fallback to 1xRTT
E-UTRAN
MME
Serving/PDN GW
SGi
1xRTT CS Access
1xRTT MSC
1xCS IWS
S102
S11 S1-MME
S1-U
A1
A1
Tunnelled 1xRTT messages
1xCS CSFB
UE
1xCS CSFB
UE
S102 is the
reference point
between MME and
1xCS interworking
solution
Tunneling of
messages between
1xRTT MSC and UE
November 2012 | LTE measurements| 262
CS fallback to 1xRTT
November 2012 | LTE measurements| 263
CS fallback to 1xRTT
UE
eNodeB
EUTRAN cell
RRC connection release message
with RedirectedCarrierInfo to
1xRTT
1xRTT cell(s)
UE will search for
suitable cell on
UARFCN and initiate
CS connection
RRC connection release with redirection without SysInfo
Mandatory
for UE
supporting
CSFB
to 1xRTT
MME
CSFB Info
CSFB to 1xRTT
Enhancement: UE can pre-register in 1xRTT network
November 2012 | LTE measurements| 264
CS fallback to 1xRTT E-UTRAN
1xRTT
MSC1xCS IWSMMEUE
UE CONTEXT MODIFICATION REQUEST (CS Fallback Indicator)
UE decision to
perform MO call in
1xCS
RRCConnectionRelease
with redirection to 1xRTT
S-GW/
P-GW
EXTENDED SERVICE REQUEST (with service type CSFB)
UE CONTEXT MODIFICATION RESPONSE
MO call establishment in 1xRTT network
UE is EPS attached and registered with 1xRTT CS
UE context release
Optional measurement
reports
UE CONTEXT RELEASE REQUEST
Suspend Notification
Suspend Acknowledge
November 2012 | LTE measurements| 265
CS fallback to 1xRTT
MobilityFromEUTRACommand
UE EUTRAN
HandoverFromEUTRAPreparationRequest
UE EUTRAN
ULHandoverPreparationTransfer
UE EUTRAN
enhanced 1xCSFB (e1xCSFB)
1) Prepare for
handover,
search for
1xRTT
2) Info about
1xRTT ->
tunnelled via
S102
3) Includes
1xRTT channel
assignment
Time flow
Enhancement: UE can pre-register in 1xRTT network
November 2012 | LTE measurements| 266
CS fallback to 1xRTT
MobilityFromEUTRACommand
UE EUTRAN
HandoverFromEUTRAPreparationRequest
UE EUTRAN
ULHandoverPreparationTransfer
UE EUTRAN
enhanced 1xCSFB (e1xCSFB) + concurrent HRPD handover
1) Prepare for
handover,
search for
1xRTT + HRPD
2) Trigger 2
messages with
info about
1xRTT + HRPD
3) Redirection
to 1xRTT and
handover to
HRPD
Time flow
Enhancement: UE can pre-register in 1xRTT network
ULHandoverPreparationTransfer
UE EUTRAN
November 2012 | LTE measurements| 267
LTE-eHRPD Handover
Overview
November 2012 | LTE measurements| 268
InterRAT Network Architecture Eg CDMA2000 1xEVDO
November 2012 | LTE measurements| 269
EUTRAN – eHRPD non-roaming
i.e. US subscriber, connected
To home network, leaves
LTE coverage area
November 2012 | LTE measurements| 270
EUTRAN – eHRPD, roaming case
i.e. European subscriber
visiting US, connected to roaming
network and leaving LTE
coverage area
November 2012 | LTE measurements| 272
Mobility between LTE and HRPD Radio Access Aspects
HRPD active to EUTRAN is
always cell reselection
(via RRC idle)
No handover to
EUTRAN
November 2012 | LTE measurements| 273
3 Step Procedure
E-UTRAN needs
to decide, that
HO to HRPD
is required
HO preparation
Connection Request
issued by UE to
HRPD, HRPD prepares
for the arrival of the UE
HO execution
Traffic Channel Assignment
command is delivered
to UE, re-tune radio to
HRPD channel, acquire
HRPD channel, session
configuration
UE attached
to E-UTRAN
Ability of pre-
registration is
indicated
on PBCCH
Pre-registration
• Reduces time for cell re-selection or handover
• Reduces risk of radio link failure
Video over LTE Testing the next step in the end user experience
November 2012 | LTE measurements| 278
l Cisco quote 06/2011
l Internet video is now 40 percent of
consumer Internet traffic, and will reach
62 percent by the end of 2015, not
including the amount of video ex-
changed through P2P file sharing. The
sum of all forms of video (TV, video
on demand [VoD], Internet, and P2P)
will continue to be approximately 90
percent of global consumer traffic by 2015.
l IDC quote 06/2011
l The fast-growing smartphone market, which will
grow more than four times the rate of the overall
mobile phone market this year, is being fuelled
by falling average selling prices, increased
phone functionality, and lower-cost data plans
among other factors, which make the devices
more accessible to a wider range of users.
Introduction
November 2012 | LTE measurements| 279
Node B
Internet
SGW PGW
MME PCRF
EPC / IMS
Node B
Impact due to
l Multipath propagation
l Speed
l …
Impact due to
l Packet delay
l Packet jitter
l Packet loss
l …
Introduction Network view
November 2012 | LTE measurements| 280
l Main use cases from a test engineer (operator, manufacturer) perspective:
l Exploring the performance of mobile equipment from the end user perspective
l Measuring E2E throughput with realistic radio conditions
l Evaluating mobility performance
Introduction Testing real life conditions in the lab
l Important aspect for end user perspective: Error free video reception
R&S®CMW500
emulates LTE
network
R&S®AMU200
baseband fader
simulates real life
radio conditions
Contest SW
provides
automation
and reporting
capabilities
CMW-PQA
November 2012 | LTE measurements| 281
Video transmission over LTE Video quality…
l … is the perceived degradation of a processed video in
comparison to an ideal reference or the reality
l … can be used as an evaluation criteria for any kind of video
transmission or processing system as signal impairments will
happen in different stages
l … can be categorized in two basic types of video quality
assessment
l Subjective quality assessment
l Objective quality assessment
November 2012 | LTE measurements| 282
Receiver
Video transmission over LTE The video processing chain and possible sources for video degradation
Encoder
Uncompressed video
SDI
SMPTE249/292/424
Redundant
information (static
image parts) and
irrelevant data
(details) is omitted
Decoder TX RX Video processor
Output on
screen Restoring the video
information; i.e. the
picture sequence
including redundant
data
Scaling and
conversion to output
format
Transmission
link
(IP, cellular,
broadcast, etc.)
• Encoding artifacts
(blocking)
• Video / audio delay
• Buffer rules are
violated
Impairments on the
transmission link
can cause loss of
information despite
active error
correction
The decoder is usually the less
critical component. But in
conjunction with the video
processor, errors during the
conversion process (e.g. de-
interlacing) are possible
November 2012 | LTE measurements| 283
Video transmission over LTE Subjective quality assessment
l Subjective video quality assessments are defined in ITU-T recommendation BT.500
l Example procedure:
A group of trained experts judge the video quality in a scale ranging from bad to excellent. The assessments are averaged and result in to a Mean Opinion Score (MOS).
l Advantages:
l Subjective assessment provides the best results, as the ultimate measure for video quality is the human eye
l Disadvantages:
l Time consuming and expensive
l Automation not possible
Mean Opinion Score (MOS)
MOS Quality
5 Excellent
4 Good
3 Fair
2 Poor
1 Bad
November 2012 | LTE measurements| 284
Video transmission over LTE Objective quality assessment
l Mathematical calculation that approximate averaged results of
subjective quality assessment
l Divided into three categories:
l Full reference methods (FR)
l Reduced reference methods (RR)
l No-reference methods (NR)
l Advantage:
l Assessment automation is possible for various applications
l Disadvantages:
l Correlation with the actual perceived video quality is not always ensured
l Many different metrics for specific purposes exist
November 2012 | LTE measurements| 285
l Most commonly used for quality measurements for image compression.
l Simple mathematical calculation but poor correlation with subjective methods:
l Digital pixel values do not exactly represent the light stimulus on the human eye
l The summation is averaging errors without weighting them
l The same PSNR values may result from different kind of structural errors
Video transmission over LTE Objective metric – peak signal-to-noise ratio (PSNR)
I(i,j) = original pixel
K(i,j) = reconstructed pixel
MAX = maximum possible pixel value
Unit: dB
Value range: 0 - ∞ dB; the higher, the better
21
0
1
0
2
10
),(),(1
)(log10
jiKjiImn
MSE
MSE
MAXPSNR
n
j
m
i
I
November 2012 | LTE measurements| 286
l Improvement to traditional methods for quality measurements to improve consistency with human eye perception.
l Complex mathematical calculation but fairly good correlation with subjective methods.
Video transmission over LTE Objective metric – structural similarity (SSIM)
Reference:
Z. Wang, A. C. Bovik, H. R. Sheikh and E. P. Simoncelli, "Image quality assessment: From
error visibility to structural similarity," IEEE Transactions on Image Processing, vol. 13, no. 4,
pp. 600-612, Apr. 2004.
Luminance
Measurement
Luminance
Measurement
Luminance
Comparison
Contrast
Comparison
Structure
Comparison
Combination
Contrast
Measurement
Contrast
Measurement
+
+
÷
÷
Signal x
Signal y
Similarity
Measure
))((
)2)(2(),(
2
22
1
22
21
CC
CCyxSSIM
yxyx
xyyx
Unit: -
Value range: 0 - 1; the higher, the better
November 2012 | LTE measurements| 287
Video transmission over LTE Correlation of objective metric with MOS
(MSSIM = Mean SSIM)
Reference:
Z. Wang, A. C. Bovik, H. R. Sheikh and E. P. Simoncelli, "Image quality assessment: From
error visibility to structural similarity," IEEE Transactions on Image Processing, vol. 13, no. 4,
pp. 600-612, Apr. 2004.
November 2012 | LTE measurements| 288
Video transmission over LTE Metric – visible error
0
0,2
0,4
0,6
0,8
1
1,2
1 3 5 7 9 11 13 15 17 19 21 23
Frame
SS
IM
Not visible
Not visible
Visible 1
Visible 2
6 Frames Visible Error
l The shown objective metrics and their correlation with MOS are
calculated frame based
l Temporal masking effects need to be considered:
l Additional condition: e.g. for at least 6 frames SSIM below 0.7 (25 fps video)
November 2012 | LTE measurements| 289
Video transmission over LTE Demo
November 2012 | LTE measurements| 290
Video transmission over LTE Testing real life conditions in the lab
PC
Contest
TC Control
Video
via MHL
or HDMI
RF
November 2012 | LTE measurements| 291
Video transmission over LTE R&S®VTE Video Tester
l Source, sink and dongle testing on MHL 1.2 interfaces and in the future also HDMI 1.4c, etc.
l Realtime difference picture analysis for testing video transmissions over LTE
l Combined protocol testing and audio/video analysis
l Future-ready, modular platform accommodating up to three test modules
l Localized touchscreen user interface
l Integrated test automation and report generation
R&S®VTE Video Tester
November 2012 | LTE measurements| 292
Video transmission over LTE Mobile high definition link (MHL)
MHL is…
l the leading audio/video interface for mobile devices
l utilizes the existing Micro-USB connector
l provides power to the mobile device
l Single Transition Minimized Differential Signaling (TMDS) channel:
l Carries video, audio and auxiliary data
l Bit stream is modulated by a clock signal
l Single-wire Control Bus (CBUS)
l Configuration and status exchange
l Replaces the DDC bus in HDMI
l Carries the MHL Sideband Channel (MSC) which provides high level control functions
l VBUS and associated ground
l Provide power between sink and source
l 5V, max. 0.5 A
November 2012 | LTE measurements| 293
Summary
l Video and voice are important services gaining momentum for
the fastest developing radio access technology ever - LTE
l Beside LTE functionality, testing voice/video quality is
essential to judge a good receiver implementation
l R&S provides you with profound expertise and
test solutions on both aspects
l Complete LTE test portfolio ranging from early R&D via IOT
and field testing until conformance and production
l Supplier of a complete range of TV broadcasting transmission,
monitoring and measurement equipment
November 2012 | LTE measurements| 294
There will be enough topics
for future trainings
Thank you for your attention!
Comments and questions welcome!